Lithium-ion battery anode binder and anode electrode based on in-situ cross-linking esterification

Abstract

The present application relates to the technical field of lithium battery negative electrode material binder preparation, more particularly to a lithium ion battery negative electrode binder and negative electrode sheet based on in-situ cross-linking esterification.The present application mixes polyacrylic acid binder, cyclodextrin-based material and catalyst, and disperses them in a solvent to prepare a premixed binder; the premixed binder is mixed with a silicon-based negative electrode active material and a conductive agent, and is coated on the surface of a current collector, and the solvent is dried; during the drying process, the carboxyl groups of the polyacrylic acid binder and the hydroxyl groups of the cyclodextrin-based material undergo in-situ cross-linking esterification under the catalysis of the catalyst, forming a three-dimensionally cross-linked bonding network.This strong bonding network can effectively alleviate the swelling effect of the silicon-based negative electrode sheet during the cycling process, endowing the electrode with excellent structural stability, and in combination with the internal cavity structure of the cyclodextrin-based material, can provide additional diffusion channels for lithium ions, improving the rate performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of lithium battery anode material binder preparation technology, and more specifically, to lithium-ion battery anode binders and anode sheets based on in-situ crosslinking esterification. Background Technology

[0002] During the charging and discharging process of lithium-ion batteries, silicon in the silicon-based negative electrode undergoes an alloying reaction with lithium ions, forming Li₂ at room temperature. 15 The silicon-based anode material has a Si4 phase, thus possessing a high theoretical specific capacity. Furthermore, it exhibits a moderate voltage plateau and is abundant in the Earth's crust. Therefore, it is considered the most promising next-generation lithium-ion battery anode material to replace graphite.

[0003] During battery cycling, silicon undergoes a volume change of up to 300% during lithium intercalation, leading to continuous rupture and formation of the SEI film, consuming limited lithium sources, and severely damaging the electrode structure, resulting in significant capacity decay in lithium-ion batteries. Polyacrylic acid (PAA), a linear polymer rich in carboxyl groups, is widely used as a binder for silicon-based anodes due to its ability to form abundant hydrogen bonds with hydroxyl groups on the silicon surface, thus mitigating the volume expansion effect of silicon to some extent. However, PAA has poor strength and toughness, making it difficult to meet the requirements of long-cycle lithium-ion batteries. Towards the end of the cycle, electrode structure collapse and silicon-based anode particles are prone to pulverization and detachment, leading to rapid capacity decay. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a lithium-ion battery anode binder and anode sheet based on in-situ crosslinking esterification. The lithium-ion battery anode binder based on in-situ crosslinking esterification uses polyacrylic acid binder and cyclodextrin-based materials as raw materials. During the drying process, under the catalysis of a catalyst, the polyacrylic acid binder and cyclodextrin-based materials undergo in-situ crosslinking esterification, resulting in a three-dimensional crosslinked bonding network. This robust bonding network effectively alleviates the expansion effect of the silicon-based anode during cycling, endowing the silicon-based anode with excellent structural stability. Simultaneously, combined with the internal cavity structure of the cyclodextrin-based material, it provides additional diffusion channels for lithium ions, improving the rate performance and lithium-ion conductivity of the silicon-based anode. Furthermore, the use of the lithium-ion battery anode binder based on in-situ crosslinking esterification enhances the mechanical strength of the polyacrylic acid binder.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention protects a lithium-ion battery anode binder based on in-situ crosslinking esterification. The lithium-ion battery anode binder based on in-situ crosslinking esterification is obtained by in-situ crosslinking esterification of polyacrylic acid binder and cyclodextrin-based materials under catalysis. Specifically: A premixed adhesive is prepared by mixing and dispersing polyacrylic acid binder and cyclodextrin-based material in a solvent.

[0006] After mixing the premixed binder with the catalyst dispersion, the solvent is dried. During the drying process, the carboxyl groups of the polyacrylic acid binder and the hydroxyl groups of the cyclodextrin-based material undergo in-situ cross-linking esterification under the catalysis of the catalyst, forming a three-dimensional cross-linked bonding network, thus obtaining a lithium-ion battery negative electrode binder based on in-situ cross-linking esterification.

[0007] Preferably, the cyclodextrin-based material is selected from one or more of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and γ-cyclodextrin derivatives.

[0008] Preferably, the polyacrylic acid binder is selected from one or more of basic linear polyacrylic acid, polyacrylates, and acrylic copolymers. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification of this invention has universality and can function in different types of polyacrylic acid binders.

[0009] Preferably, the catalyst is selected from at least one of sodium hypophosphite, hypophosphite, potassium hypophosphite, sodium citrate, and sodium tartrate.

[0010] Preferably, the mass ratio of polyacrylic acid binder to cyclodextrin-based material is 1:0.05~0.1. By controlling the amounts of polyacrylic acid binder and cyclodextrin-based material, the crosslinking density and mechanical strength of the lithium-ion battery anode binder based on in-situ crosslinking esterification can be controlled, thereby improving the overall performance. Insufficient cyclodextrin-based material has no effect; excessive cyclodextrin-based material results in a low proportion of polyacrylic acid and poor adhesion.

[0011] Preferably, the mass of the catalyst is 0.1% to 10% of the total mass of the polyacrylic acid binder and cyclodextrin-based material. The amount of catalyst used must be appropriate, neither too much nor too little. Too much catalyst will affect the proportion of active material in the negative electrode, while too little catalyst will hinder the catalytic reaction, preventing the reaction from proceeding normally and affecting the electrochemical performance of the negative electrode. The mass fraction of the catalyst dispersion is 0.5% to 2.5%, and more preferably 1%.

[0012] Preferably, the drying method is selected from blower drying, vacuum drying, microwave drying or infrared drying, and the drying conditions are: 50°C~150°C for 2h~24h.

[0013] This invention also protects a lithium-ion battery negative electrode sheet, which is prepared using the above-mentioned lithium-ion battery negative electrode binder based on in-situ crosslinking esterification.

[0014] Preferably, the negative electrode sheet is prepared according to the following steps: A premixed adhesive is prepared by mixing polyacrylic acid binder and cyclodextrin-based material and dispersing them in a solvent.

[0015] The silicon anode active material, conductive agent and premixed binder are mixed and a catalyst dispersion is added. The mixture is stirred and dispersed evenly to prepare an electrode slurry.

[0016] The electrode paste is coated onto the current collector and then dried. During the drying process, the carboxyl groups of the polyacrylic acid binder, the hydroxyl groups of the cyclodextrin-based material, and the hydroxyl groups on the silicon anode active material undergo in-situ cross-linking and esterification under the catalysis of the catalyst to obtain the anode sheet.

[0017] Preferably, the silicon anode active material is selected from micron-sized silicon, nano-sized silicon, silicon suboxide, or silicon carbon.

[0018] During the preparation of premixed binder or catalyst dispersion, a stirrer is used to continuously stir at a speed of 500 rpm to 1500 rpm for 10 min to 60 min, or ultrasonic oscillation or high shear stirring is used to ensure uniform mixing.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. In the synthesis of lithium-ion battery anode binders based on in-situ crosslinking esterification, this invention uses polyacrylic acid binders and cyclodextrin-based materials to form a robust three-dimensional crosslinked network structure under catalysis. At this time, the carboxyl groups of the polyacrylic acid binder and the hydroxyl groups of the cyclodextrin-based material undergo crosslinking esterification, which can effectively enhance the mechanical strength of the lithium-ion battery anode binders based on in-situ crosslinking esterification, and simultaneously improve Young's modulus and toughness. This can effectively dissipate the energy generated by the volume expansion of the silicon-based anode sheet of lithium-ion batteries during lithium insertion / deintercalation.

[0020] In addition, the carboxyl groups of the polyacrylic acid binder can undergo in-situ cross-linking and esterification with the hydroxyl groups on the silicon anode active material under the catalysis of a catalyst, thereby enhancing the adhesion and mechanical strength between the lithium-ion battery anode binder based on in-situ cross-linking and esterification and the silicon anode.

[0021] 2. The cyclodextrin-based material of the present invention has an internal cavity with a suitable pore size, which can serve as a channel for lithium-ion diffusion, enhance the ionic conductivity of the lithium-ion battery anode binder based on in-situ cross-linking esterification, and is beneficial to improving the rate performance of silicon-based anode sheets and improving the fast charging capability of lithium-ion batteries.

[0022] 3. By adjusting the ratio of polyacrylic acid binder to cyclodextrin-based material, this invention can regulate the mechanical strength and crosslinking density of the three-dimensional crosslinked network structure, thereby obtaining a negative electrode with superior electrochemical performance.

[0023] 4. This invention uses in-situ thermal polymerization during the electrode drying process, which is completed during the electrode drying process without additional energy consumption or changes to the process flow. This reaction characteristic not only improves electrode performance but also does not increase energy consumption and is compatible with existing processes.

[0024] 5. The preparation process of this invention is low-cost and suitable for large-scale production. Cyclodextrin-based materials are inexpensive, resulting in lower costs. By replacing part of the polyacrylic acid binder, no additional costs are required. Attached Figure Description

[0025] Figure 1 The diagram shows the cycle test results of button half-cells assembled using the negative electrode sheets of Examples 1-2 and Comparative Examples 1-3.

[0026] Figure 2 The stress-strain curves of the adhesive in Example 1 and Comparative Examples 1 to 2 are shown.

[0027] Figure 3 The image shows a scanning electron microscope image of the surface of the negative electrode sheet of Example 1 after 150 cycles at 2C.

[0028] Figure 4 The image shows a scanning electron microscope image of the surface of the negative electrode sheet of Comparative Example 1 after 150 cycles at 2C.

[0029] Figure 5 The image shows a scanning electron microscope image of the surface of the negative electrode sheet of Comparative Example 2 after 150 cycles at 2C.

[0030] Figure 6 The diagram shows the cycle test results of the coin cell assembled using the negative electrode sheets of Example 1 and Comparative Example 1.

[0031] Figure 7 The diagram shows the cycle test results of the pouch cell assembled using the negative electrode sheets of Example 1 and Comparative Example 1. Detailed Implementation

[0032] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] A method for preparing a negative electrode sheet includes the following steps: S1. Polyacrylic acid binder and cyclodextrin-based material are mixed and dispersed in a solvent to prepare a premixed binder; the catalyst is dispersed in a solvent to prepare a catalyst dispersion.

[0034] S2. Mix the silicon anode active material, conductive agent and premixed binder, add catalyst dispersion, stir and disperse evenly to prepare electrode slurry.

[0035] S3. According to the required coating density, the electrode paste is evenly coated on the surface of the current collector and placed in an oven to dry. During the drying process, the carboxyl groups of the polyacrylic acid binder, the hydroxyl groups of the cyclodextrin-based material, and the hydroxyl groups on the silicon negative electrode active material undergo in-situ cross-linking esterification under the catalysis of the catalyst to obtain the negative electrode sheet.

[0036] In some embodiments, the polyacrylic adhesive is selected from one or more of basic linear polyacrylic acid, polyacrylates (such as sodium polyacrylate, lithium polyacrylate), and acrylic copolymers.

[0037] In some embodiments, the cyclodextrin-based material is selected from one or more of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and γ-cyclodextrin derivatives.

[0038] In some embodiments, the catalyst is selected from at least one of sodium hypophosphite, hypophosphite, potassium hypophosphite, sodium citrate, and sodium tartrate.

[0039] The catalyst is 0.1% to 10% of the total mass of the polyacrylic acid binder and cyclodextrin-based material. The catalyst is selected from substances capable of catalyzing the esterification reaction of the polyacrylic acid binder and cyclodextrin-based material.

[0040] The solvents used above are selected from at least one of water, ethanol, acetone, NMP, DMSO, DMF, and ethyl acetate.

[0041] In some embodiments, the premixed binder and catalyst dispersion are stirred at a speed of 500 rpm to 1500 rpm for 10 min to 60 min using a stirrer, or by ultrasonic oscillation or high-shear stirring, to ensure that the solution is uniformly mixed to a clear state.

[0042] In some embodiments, the drying method used is selected from one or a combination of several of the following: forced-air drying, vacuum drying, microwave drying, and infrared drying.

[0043] In some embodiments, the drying conditions are: drying at 50°C to 150°C for 2 hours to 24 hours.

[0044] Compared with the prior art, the technical solution of the present invention has the following advantages: 1. Simplified reaction conditions. Existing technologies use pre-crosslinked polyacrylic acid as a binder, which typically requires additional processes and energy consumption. Furthermore, increasing the binder viscosity necessitates changes to process parameters and the use of additional solvents. This invention employs thermal crosslinking during electrode drying, enabling in-situ completion during the drying process without additional energy consumption or process modifications, resulting in simpler reaction conditions.

[0045] 2. The bonding network exhibits uniform cross-linking and high strength. In the negative electrode sheet, the binding ability of the in-situ cross-linked binder for silicon carbon is much higher than that of the non-in-situ polymerized binder, forming a uniform and robust three-dimensional cross-linked bonding network in the electrode structure. This characteristic can significantly improve the structural stability of the silicon carbon electrode and enhance its cycle stability.

[0046] 3. Improved rate performance. Traditional polyacrylic acid binders have poor ionic conductivity, while the cyclodextrin-based material used in this invention has an internal cavity with a suitable pore size, which can serve as a channel for lithium-ion diffusion, enhancing the ionic conductivity of the lithium-ion battery negative electrode binder based on in-situ cross-linking esterification. This is beneficial for improving the rate performance of the negative electrode sheet and increasing the fast charging capability of the lithium-ion battery.

[0047] 4. Improved cycle stability and enhanced mechanical integrity of the negative electrode. In in-situ cross-linked esterified lithium-ion batteries, the binder of the negative electrode exhibits excellent mechanical properties. Its superior toughness helps alleviate volume expansion of the negative electrode and maintain its structural integrity. Experiments show that SEM characterization of the negative electrode of lithium-ion batteries using in-situ cross-linked esterified lithium-ion batteries reveals a significant reduction in the number of cracks. This not only enhances the integrity of the negative electrode but also reduces the contact between the internal silicon and the electrolyte, thereby effectively suppressing side reactions and extending the lifespan of the lithium-ion battery.

[0048] The technical solution of the present invention will be further described below with reference to specific embodiments and comparative examples, as follows: Coin cell half-cells were assembled, and their negative electrode electrochemical performance was studied. The assembly method was as follows: a negative electrode sheet was used as the negative electrode, a lithium sheet as the positive electrode, a Celgard 2500 separator as the separator, and LB015 as the electrolyte. Assembly was performed in the following order: negative electrode shell - lithium sheet - electrolyte - separator - electrolyte - negative electrode sheet - positive electrode shell. The cells were then sealed using a coin cell sealing machine.

[0049] Example 1 A method for preparing a lithium-ion battery negative electrode binder based on in-situ crosslinking esterification includes the following steps: S1. Dissolve 0.1g of polyacrylic acid and 0.01g of β-cyclodextrin together in water and stir to form a uniform premixed binder.

[0050] S2. Disperse the catalyst sodium hypophosphite in a solvent to prepare a catalyst dispersion.

[0051] S3. After mixing the premixed binder with the catalyst dispersion, dry it in a 70°C oven for 24 hours to obtain a lithium-ion battery anode binder based on in-situ cross-linking esterification.

[0052] A method for preparing a negative electrode sheet includes the following steps: S1. Weigh out the silicon anode active material (CVD silicon carbon particles), conductive agent (Super P:SWCMTs=9:1) and premixed binder (polyacrylic acid:β-cyclodextrin=1:0.1) according to the mass ratio of silicon anode active material: conductive agent: binder = 8:1:1. Then add 0.4wt% (mass fraction of the total mass of binder) of sodium hypophosphite catalyst and stir at 500rpm for 6h at room temperature to obtain silicon carbon electrode slurry.

[0053] S3. The silicon-carbon electrode paste is uniformly coated on the surface of the copper current collector using a scraper coating method, and then dried in a 70°C forced-air oven for 24 hours to obtain the negative electrode sheet.

[0054] Comparative Example 1 A method for preparing an adhesive and a negative electrode sheet is the same as the preparation steps in Example 1, except that no catalyst and β-cyclodextrin are added, i.e., the raw material is only polyacrylic acid. Figure 1 As shown, the negative electrode of Comparative Example 1 exhibits poor cycle performance and rate performance. Figure 4 As shown, after cycling, a large number of cracks appeared on the surface of the negative electrode sheet of Comparative Example 1, indicating that the electrode was severely pulverized and the binder could not effectively alleviate the volume expansion effect of the negative electrode sheet.

[0055] Comparative Example 2 A method for preparing a binder and a negative electrode sheet is the same as the preparation steps in Example 1, except that no catalyst is added. Figure 1 As shown, compared with Comparative Example 1, the negative electrode of Comparative Example 2 has improved cycle performance and rate performance, but both are inferior to those of Example 1. Figure 2 The stress-strain analysis showed that, compared to Comparative Example 1, the tensile fracture rate was slightly increased in Comparative Example 2 due to the addition of β-cyclodextrin, indicating that β-cyclodextrin, as a plasticizer, improved the toughness of the binder. Figure 5 As shown, after cycling, although only a small number of cracks were generated on the surface of the negative electrode of Comparative Example 2, they were still more than those of Example 1. This indicates that although adding only β-cyclodextrin without adding a catalyst can slightly improve battery performance, the electrode pulverization is still quite serious and it is difficult to effectively alleviate the volume expansion effect of the negative electrode.

[0056] like Figure 1As shown, compared with Comparative Examples 1 and 2, the negative electrode of Example 1 exhibits improved cycle performance, and the negative electrode of Example 1 demonstrates the best cycle stability, with a capacity of 895 mAh g after 350 cycles. -1 The negative electrode sheet of Example 1 exhibits excellent rate performance, with a capacity of 640 mAh g at 5C rate. -1 It is much higher than the 244 mAh g of Comparative Example 1. -1 Compared with Comparative Example 2, 489mAh g -1 .like Figure 2 As shown, compared with Comparative Examples 1 and 2, the lithium-ion battery negative electrode binder based on in-situ crosslinking esterification in Example 1 has a higher Young's modulus (59.35 MPa) and tensile elongation at break (1.22%). This good mechanical strength can effectively alleviate the volume expansion of the negative electrode sheet and maintain the integrity of the negative electrode sheet structure after long cycles. Figures 3-5 The comparison shows that the negative electrode sheet of Example 1 has high stability. The lithium-ion battery negative electrode binder based on in-situ cross-linked esterification can effectively alleviate the volume expansion effect of the negative electrode sheet, thus exhibiting excellent cycle life.

[0057] After 350 cycles at 0.5C, the negative electrode of Example 1 retained a capacity of up to 90.3%. Figure 6 As shown, the negative electrode of Comparative Example 1 has a capacity retention rate of only 76.4%.

[0058] Using an NCM811 electrode as the positive electrode, and the negative electrode sheets from Example 1 and Comparative Example 1 as the negative electrodes respectively, a commercially available high-nickel ternary electrolyte was used as the electrolyte, and a Celgard 2500 separator was used as the separator. Through a Z-shaped stacking process, the separator was folded repeatedly in a Z-shape, and the positive and negative electrode sheets were alternately inserted into the separator stack to assemble a soft-pack battery. Figure 7 As shown, the negative electrode of Example 1 exhibits excellent cycle stability. After 1000 cycles at 1C, the capacity retention rate is as high as 80%, while the capacity retention rate of the pouch battery assembled using the negative electrode of Comparative Example 1 decreases to 80% with only 730 cycles.

[0059] Comparative Example 3 A method for preparing a negative electrode sheet is the same as the preparation steps in Example 1, except that the mass of β-cyclodextrin is replaced from 0.01g to 0.02g, i.e., the mass ratio of polyacrylic acid to β-cyclodextrin is 1:0.2 (0.1g of polyacrylic acid and 0.02g of β-cyclodextrin are added). Figure 1 As shown, the rate performance is similar to that of the negative electrode in Comparative Example 2.

[0060] Example 2 A method for preparing a negative electrode sheet is the same as the preparation steps in Example 1, except that the mass of β-cyclodextrin is replaced from 0.01g to 0.005g, i.e., the mass ratio of polyacrylic acid to β-cyclodextrin is 1:0.05 (0.1g of polyacrylic acid and 0.005g of β-cyclodextrin are added). Figure 1 As shown, compared with Comparative Example 1 and Comparative Example 2, the cycle performance and rate performance of the negative electrode sheet in Example 2 are effectively improved.

[0061] Comparative Examples 1, 2, 2, and 3 revealed that an effective improvement in cycle performance and rate performance can only be achieved when the mass ratio of polyacrylic acid to β-cyclodextrin is within a certain range (1:0.05~0.1).

[0062] Example 3 A method for preparing a negative electrode sheet is the same as the preparation steps in Example 1, except that the drying conditions are changed from 70°C, 24h to 50°C, 24h.

[0063] Example 4 A method for preparing a negative electrode sheet is the same as the preparation steps in Example 1, except that the drying conditions are changed from 70°C, 24h to 150°C, 2h.

[0064] In summary, this invention provides a method for preparing a lithium-ion battery negative electrode binder and a negative electrode sheet based on in-situ cross-linked esterification. By constructing a three-dimensional esterified cross-linked binder network in situ within the silicon negative electrode active material, the volume expansion of silicon negative electrode active material particles during cycling is effectively mitigated, enhancing the mechanical integrity of the electrode sheet. Simultaneously, the internal cavity structure of the cyclodextrin-based material can serve as a lithium-ion diffusion channel, improving the ionic conductivity of the binder and enhancing rate performance. The assembled silicon negative electrode active material pouch battery exhibits superior cycle stability, solving the technical problems of negative electrode sheet pulverization due to cycle expansion and low binder ionic conductivity.

[0065] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lithium-ion battery anode binder based on in-situ crosslinking esterification, characterized in that, The lithium-ion battery anode binder based on in-situ cross-linking esterification is obtained by in-situ cross-linking esterification of polyacrylic acid binder and cyclodextrin-based materials under catalysis. Specifically: After mixing polyacrylic acid binder, cyclodextrin-based material, catalyst and solvent, the solvent is dried. During the drying process, the carboxyl groups of polyacrylic acid binder and the hydroxyl groups of cyclodextrin-based material undergo in-situ cross-linking esterification under the catalysis of the catalyst to form a three-dimensional cross-linked bonding network, thus obtaining a lithium-ion battery negative electrode binder based on in-situ cross-linking esterification.

2. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification according to claim 1, characterized in that, The cyclodextrin-based material is selected from one or more of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and γ-cyclodextrin derivatives.

3. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification according to claim 1, characterized in that, The polyacrylic adhesive is selected from one or more of basic linear polyacrylic acid, polyacrylates, and acrylic copolymers.

4. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification according to claim 1, characterized in that, The catalyst is selected from at least one of sodium hypophosphite, hypophosphite, potassium hypophosphite, sodium citrate, and sodium tartrate.

5. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification according to claim 1, characterized in that, The mass ratio of polyacrylic acid binder to cyclodextrin-based material is 1:0.05~0.

1.

6. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification according to claim 1, characterized in that, The mass of the catalyst is 0.1% to 10% of the total amount of polyacrylic acid binder and cyclodextrin-based material.

7. The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification according to claim 1, characterized in that, The drying conditions are: 50°C to 150°C for 2 hours to 24 hours.

8. A negative electrode sheet, characterized in that, The lithium-ion battery negative electrode binder based on in-situ crosslinking esterification as described in claim 1 is used.

9. The negative electrode sheet according to claim 8, characterized in that, The negative electrode sheet is prepared according to the following steps: A premixed adhesive is prepared by mixing polyacrylic acid binder and cyclodextrin-based material and dispersing them in a solvent. The silicon anode active material, conductive agent and premixed binder are mixed, and catalyst dispersion is added. The mixture is stirred and dispersed evenly to prepare an electrode slurry. The electrode paste is coated onto the current collector and then dried. During the drying process, the carboxyl groups of the polyacrylic acid binder, the hydroxyl groups of the cyclodextrin-based material, and the hydroxyl groups on the silicon anode active material undergo in-situ cross-linking and esterification under the catalysis of the catalyst to obtain the anode sheet.

10. The negative electrode sheet according to claim 9, characterized in that, The active material for silicon anodes is selected from micron-sized silicon, nano-sized silicon, silicon suboxide, or silicon carbon.

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