A silicon-oxygen negative electrode material with a surface-connected binder, its preparation method and application

Abstract

The present invention provides a silicon-oxygen negative electrode material with a surface-connected binder, a preparation method and an application thereof. The silicon-oxygen negative electrode material with a surface-connected binder includes a silicon-oxygen negative electrode material and a binder connected to its surface. The binder includes a first polymer and a second polymer. The polymerization monomers of the first polymer include any one or a combination of at least two of acrylate monomers, acrylamide monomers, acrylonitrile monomers or styrene monomers. The polymerization monomers of the second polymer include isocyanate monomers and an ethylene oxide polymer containing terminal hydroxyl groups. The silicon-oxygen negative electrode material of the present invention can improve the swelling and aging problems during cycling, improve the adhesiveness, and enhance the comprehensive performance of the material, so that the lithium-ion battery containing the same has a high initial Coulomb efficiency and cycling stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and relates to a silicon-oxygen negative electrode material, a preparation method and an application thereof, in particular to a silicon-oxygen negative electrode material with a binder connected to its surface, a preparation method and an application thereof. Background Art

[0002] Due to advantages such as high energy density, small volume, and environmental friendliness, lithium-ion batteries have been widely used in fields such as 3C (electronic digital), energy storage, and power. Improving the comprehensive performance of lithium-ion batteries, including energy density and cycle life, is crucial in the industry. Existing maturely applied negative electrode materials, such as silicon-based negative electrode materials, still have some natural problems and defects. For example, the adhesion between active substances and between active substances and current collectors is poor, the irreversible expansion problem of materials caused by cyclic aging, side reactions with electrolytes, and SEI film aging, etc. These problems lead to issues such as fragmentation of active powders, thereby affecting the capacity and cycle stability of the battery, and even further causing potential safety hazards to the battery.

[0003] CN110783559A discloses a modified negative electrode material, a preparation method and uses thereof. The modified negative electrode material contains a silicon-based negative electrode material containing Si / SiO x and a polymer coating layer coated on its surface. The polymer coating layer contains polymer colloid particles and networked high-molecular polymers. However, the first Coulomb efficiency of its battery can only reach 75 - 77%, and the cycle stability also needs to be further improved.

[0004] Therefore, in this field, there is a desire to develop a material that can improve the swelling and aging problems of negative electrode materials during cycling, and at the same time can improve the adhesion between active substances and between active substances and current collectors, thereby enhancing the comprehensive performance. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a silicon-oxygen negative electrode material, a preparation method and an application thereof, in particular to provide a silicon-oxygen negative electrode material with a binder connected to its surface, a preparation method and an application thereof.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a silicon-oxygen negative electrode material with a binder connected to its surface. The silicon-oxygen negative electrode material with a binder connected to its surface includes a silicon-oxygen negative electrode material and a binder connected to its surface. The binder includes a first polymer and a second polymer. The polymerization monomers of the first polymer include any one or at least two combinations of acrylate monomers, acrylamide monomers, acrylonitrile monomers, or styrene monomers. The polymerization monomers of the second polymer include isocyanate monomers and epoxyethane polymers containing terminal hydroxyl groups.

[0008] In the present invention, by connecting a first polymer and a second polymer to the surface of the silicon-oxygen negative electrode material, the first polymer is a particle structure component of acrylate, which is a dot structure on the surface of the active material, and the second polymer is a non-particle structure. The two act synergistically to jointly form a polymer coating structure on the surface of the active material, so as to improve the swelling and aging problems of the silicon-oxygen negative electrode material during the cycling process. At the same time, the adhesion between the negative electrode active materials and between the negative electrode active material and the current collector can be improved, thereby enhancing the comprehensive performance of the material.

[0009] In the present invention, the first polymer is a particle structure and the second polymer is a non-particle structure, and the first polymer and the second polymer form a polymer network on the surface of the silicon-oxygen negative electrode material.

[0010] Preferably, the silicon-oxygen negative electrode material is a silicon-based oxide negative electrode material SiOx, where x is 0-2, but does not include 0, such as 0.5, 1, 1.5 or 2.

[0011] Preferably, the acrylate monomers are selected from any one or a combination of at least two of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, sodium acrylate, lithium acrylate, acrylic acid, lithium methacrylate, methacrylic acid, lithium itaconate, itaconic acid, lithium itaconate monobutyl ester or itaconic acid monobutyl ester.

[0012] Preferably, the acrylamide monomers are selected from any one or a combination of at least two of acrylamide, methacrylamide, N-hydroxymethylacrylamide or N,N-dimethylacrylamide.

[0013] Preferably, the binder further includes cellulose, and the cellulose is mixed with the first polymer, which can improve the emulsion dispersion stability during the preparation of the first polymer.

[0014] Preferably, the cellulose is selected from any one or a combination of at least two of cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), nitrocellulose, carboxymethyl cellulose (CMC), carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose, sodium cellulose, sodium nitrocellulose or carboxyalkyl cellulose sodium.

[0015] Preferably, the isocyanate monomer is selected from any one or a combination of at least two of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), dimethylbiphenyl diisocyanate (TODI), hexamethylene diisocyanate (HDI), hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2,2,4-trimethylhexamethylene diisocyanate (TMDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), hydrogenated xylylene diisocyanate (HXDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), methylcyclohexane diisocyanate (HTDI), 1,4-cyclohexane diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate or norbornane diisocyanate.

[0016] In the present invention, the epoxyethane polymer containing terminal hydroxyl groups used is a liquid epoxyethane polymer containing terminal hydroxyl groups, and the number-average molecular weight of the epoxyethane polymer containing terminal hydroxyl groups is preferably 100 - 10,000, such as 100, 150, 200, 300, 500, 700, 800, 900, 1000, 2000, 4000, 5000, 7000, 9000 or 10,000, etc.

[0017] In the present invention, the glass transition temperature Tg of the first polymer ranges from -50 to 200 °C, such as -50 °C, -20 °C, -10 °C, 0 °C, 5 °C, 10 °C, 20 °C, 50 °C, 70 °C, 90 °C, 100 °C, 130 °C, 150 °C, 180 °C or 200 °C. Tg is obtained by differential scanning calorimetry (DSC) testing.

[0018] Preferably, the particle size of the first polymer is 200 nm - 10 μm, such as 200 nm, 400 nm, 500 nm, 800 nm, 1 μm, 3 μm, 5 μm, 8 μm or 10 μm.

[0019] In the present invention, the first polymer can be prepared by emulsion polymerization or microemulsion polymerization or suspension polymerization or minisuspension polymerization methods.

[0020] Preferably, the second polymer is obtained by in-situ polymerization on the surface of the silicon-oxygen anode material connected with the first polymer.

[0021] In the present invention, in-situ polymerization is carried out on the surface of the silicon-oxygen anode material connected with the first polymer, so that isocyanate monomers and an epoxyethane polymer containing terminal hydroxyl groups are polymerized to obtain a second polymer. The second polymer component is a polymer with good elasticity, which enhances the bonding elasticity. The first polymer is an acrylate particle structure component, forming a dot structure on the surface of the active material. The second polymer is a non-particle structure. The two act synergistically to jointly form a polymer coating structure on the surface of the active material, which can further alleviate the volume expansion problem of the silicon-oxygen anode material during the cycling process, further enhance the adhesion between the silicon-oxygen anode active materials and between the silicon-oxygen anode active material and the current collector, and thus improve the first Coulombic efficiency and cycling stability of the lithium-ion battery.

[0022] In the present invention, cellulose is added during the preparation of the first polymer. As a blend material of the first polymer, cellulose is mixed and wound together with the first polymer, which can improve the suspension stability of the emulsion and the dispersion stability and binding force during subsequent mixing with the active material.

[0023] On the other hand, the present invention provides a method for preparing the silicon-oxygen anode material with a surface-connected binder as described above. The preparation method includes the following steps:

[0024] (1) The first polymer and the silicon-oxygen anode material are added to a solvent for wet mixing to obtain a mixed slurry, and then the solvent in the mixed slurry is removed to obtain a solvent-free mixture;

[0025] (2) Isocyanate monomers, an epoxyethane polymer containing terminal hydroxyl groups, a cross-linking agent and a catalyst are mixed, and then mixed with the solvent-free mixture obtained in step (1) to carry out an in-situ polymerization reaction to obtain the silicon-oxygen anode material with a surface-connected binder.

[0026] In the present invention, the first polymer is connected to the surface of the silicon-oxygen anode material by means of wet mixing. The first polymer is an acrylate particle structure component, forming a dot structure on the surface of the active material. Then, the second polymer obtained by polymerizing isocyanate monomers and an epoxyethane polymer containing terminal hydroxyl groups through in-situ polymerization is connected to the surface of the silicon-oxygen anode material. The second polymer is a non-particle structure. The second polymer component is a polymer with good elasticity, which enhances the bonding elasticity. The wet mixing process can make the polymer components and the silicon-oxygen anode active material components mix evenly, ensuring the mixing uniformity of the two. The functional groups contained in the in-situ polymerized epoxyethane polymer can interact with the active groups on the surface of the silicon-oxygen anode material to generate chemical bonding, thereby enhancing the chemical force between the polymer structure and the silicon-oxygen anode structure. After the binder synthesis is completed, it presents a spherical or fibrous filamentous state on the surface of the active material, which is more beneficial to the improvement of the bonding force.

[0027] Preferably, the preparation method of the first polymer in step (1) includes the following steps:

[0028] Add the first polymerization monomer and initiator to an aqueous solution containing an emulsifier and / or a dispersant, carry out the first polymerization reaction to obtain a first polymer emulsion, and remove the solvent water from the obtained binder emulsion to obtain the first polymer. The first polymerization monomer includes any one or a combination of at least two of acrylate monomers, acrylamide monomers, acrylonitrile monomers, or styrene monomers.

[0029] Preferably, based on the total weight of the emulsifier, dispersant, first polymerization monomer, and initiator being 100%, the total proportion of the dispersant and emulsifier is 20.0% (such as 0.1%, 0.5%, 1.0%, 3.0%, 5.0%, 8.0%, 10.0%, 13.0%, 15.0%, 18.0%, or 20.0%), the proportion of the first polymerization monomer is 60.0% - 99.8% (such as 60.0%, 63.0%, 65.0%, 68.0%, 70.0%, 73.0%, 75.0%, 78.0%, 80.0%, 83.0%, 85.0%, 88.0%, 90.0%, 92.0%, 95.0%, 98.0%, or 99.8%), and the proportion of the initiator is 0.1% - 10.0% (such as 0.1%, 0.5%, 1.0%, 3.0%, 5.0%, 8.0%, or 10.0%).

[0030] Preferably, the total weight percentage of the emulsifier, dispersant, first polymerization monomer, and initiator in the first polymer emulsion is 2% - 30%, such as 2%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 25%, 28%, or 30%.

[0031] Preferably, the acrylate monomers are selected from any one or a combination of at least two of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, sodium acrylate, lithium acrylate, acrylic acid, lithium methacrylate, methacrylic acid, lithium itaconate, itaconic acid, lithium itaconate monobutyl ester, or itaconic acid monobutyl ester.

[0032] Preferably, the acrylamide monomers are selected from any one or a combination of at least two of acrylamide, methacrylamide, N-hydroxymethylacrylamide, or N,N-dimethylacrylamide.

[0033] Preferably, cellulose is further added to the system of the first polymerization reaction.

[0034] Preferably, the cellulose is selected from any one or a combination of at least two of cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), nitrocellulose, carboxymethyl cellulose (CMC), carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose, sodium cellulose, sodium nitrate cellulose or sodium carboxyalkyl cellulose.

[0035] Preferably, the dosage of the cellulose is 0.1%-5.0% of the total weight of the first polymer monomer, such as 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 2.0%, 3.0%, 4.0% or 5.0%.

[0036] Preferably, the emulsifier is one or a combination of at least two of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate or sodium dodecyl sulfonate;

[0037] Preferably, the dispersant is one or a combination of at least two of polyvinyl alcohol, polyvinylpyrrolidone, tetradecane, hexadecane or octadecane;

[0038] Preferably, the initiator is independently an organic peroxide initiator, an organic azo initiator, an inorganic peroxide initiator or a redox initiator.

[0039] Preferably, the organic peroxide initiator is benzoyl peroxide or dicumyl peroxide.

[0040] Preferably, the organic azo initiator is azobisisobutyronitrile or azobisisoheptonitrile.

[0041] Preferably, the inorganic peroxide initiator is ammonium persulfate, sodium persulfate or potassium persulfate.

[0042] Preferably, the redox initiator is ammonium persulfate and sodium sulfite, or ammonium persulfate and sodium bisulfite.

[0043] Preferably, the temperature of the first polymerization reaction is 35-98°C, such as 35°C, 40°C, 50°C, 55°C, 60°C, 65°C, 68°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 98°C.

[0044] Preferably, the time of the first polymerization reaction is 3-15 h, such as 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 12 h or 15 h.

[0045] Preferably, in the mixed slurry of step (1), based on the total weight of the first polymer and the silicon-oxygen anode material being 100%, the proportion of the first polymer is 0.5-10.0% (such as 0.5%, 1.0%, 2.0%, 3.0%, 5.0%, 7.0%, 9.0% or 10.0%), and the proportion of the silicon-oxygen anode material is 90.0-99.5% (such as 90.0%, 92.0%, 94.0%, 95.0%, 97.0%, 99.0% or 99.5%).

[0046] Preferably, the mixed slurry in step (1) further comprises a conductive additive.

[0047] Preferably, the conductive additive comprises one or a combination of at least two of conductive graphite, acetylene black, carbon nanotubes or conductive carbon black.

[0048] Preferably, in the mixed slurry of step (1), based on the total weight of the first polymer and the silicon-oxygen anode material being 100%, the proportion of the conductive additive is 0-5%, such as 0.5%, 1.0%, 1.5%, 2.0%, 3.0%, 4.0% or 5.0%.

[0049] Preferably, the wet mixing process in step (1) includes a resonant acoustic mixing process, a high-shear process and grinding, etc.

[0050] Preferably, the wet mixing operation in step (1) includes using one or a combination of at least two of a ball mill, an electromagnetic ball mill, a disk mill, a pin-bar grinder, a high-energy impact grinder, a fluid energy impact grinder, an opposed jet grinder, a fluidized bed jet grinder, a hammer mill or an impact grinder.

[0051] Preferably, the method for removing the solvent from the mixed slurry in step (1) is any one or a combination of at least two of vacuum drying, centrifugation, freeze drying, spray drying.

[0052] Preferably, the total weight of the isocyanate monomer and the epoxyethane polymer containing terminal hydroxyl groups in step (2) is 0.1-10.0% of the weight of the solvent-free mixture, such as 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0% or 10.0%.

[0053] Preferably, the weight ratio of the isocyanate monomer to the epoxyethane polymer containing terminal hydroxyl groups in step (2) is 1:2-5:1, such as 1:2, 1:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1.

[0054] Preferably, the amount of the crosslinking agent in step (2) is 0.1%-10.0% of the total weight of the isocyanate monomer and the hydroxyl-terminated ethylene oxide polymer, such as 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0% or 10.0%.

[0055] Preferably, the amount of the catalyst in step (2) is 0.1%-5.0% of the total weight of the isocyanate monomer and the hydroxyl-terminated ethylene oxide polymer, such as 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 4.0% or 5.0%.

[0056] Preferably, the isocyanate monomer in step (2) is selected from any one or a combination of at least two of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), dimethylbiphenyl diisocyanate (TODI), hexamethylene diisocyanate (HDI), hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2,2,4-trimethylhexane diisocyanate (TMDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), hydrogenated xylylene diisocyanate (HXDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), methylcyclohexane diisocyanate (HTDI), 1,4-cyclohexane diisocyanate, 1,4-phenylene diisocyanate (PPDI), 1,3-phenylene diisocyanate or norbornane diisocyanate.

[0057] Preferably, the hydroxyl-terminated ethylene oxide polymer is a liquid hydroxyl-terminated ethylene oxide polymer, and the number-average molecular weight of the hydroxyl-terminated ethylene oxide polymer is preferably 100-10000.

[0058] Preferably, the crosslinking agent in step (2) is selected from any one or a combination of at least two of diol crosslinking agents, triol crosslinking agents, diamine crosslinking agents, alkanolamine crosslinking agents, alicyclic alcohol crosslinking agents, aromatic alcohol crosslinking agents, allyl glycerol ether, allyl glycidyl ether or dicumyl peroxide.

[0059] Preferably, the crosslinking agent in step (2) is selected from any one or a combination of at least two of 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, glycerol, trimethylolpropane, 3,3-dichloro-4,4-diaminodiphenylmethane, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine, 2,4-diamino-3,5-dimethylthiochlorobenzene, isophoronediamine, ethanolamine, diethanolamine, triethanolamine, N,N-bis(2-hydroxypropyl)aniline, 1,4-cyclohexanediol, hydrogenated bisphenol A, dimethylenephenyl diol, hydroquinone bis-β-hydroxyethyl ether, resorcinol hydroxy ether, glycerol allyl ether, glycidyl allyl ether or dicumyl peroxide.

[0060] Preferably, the catalyst in step (2) is selected from any one or a combination of at least two of tertiary amine catalysts or organometallic compounds.

[0061] Preferably, the catalyst in step (2) is selected from any one or a combination of at least two of N,N-dimethylcyclohexylamine, dibutyltin dilaurate, bismuth 2-ethylhexanoate or bismuth neodecanoate.

[0062] Preferably, the temperature of the in-situ polymerization reaction in step (2) is 25-100 °C, such as 25 °C, 30 °C, 33 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C or 100 °C.

[0063] Preferably, the time of the in-situ polymerization reaction in step (2) is 5-50 h, such as 5 h, 10 h, 15 h, 20 h, 24 h, 28 h, 30 h, 36 h, 39 h, 40 h, 42 h, 45 h, 48 h or 50 h.

[0064] On the other hand, the present invention provides a negative electrode sheet, which includes the silicon-oxygen negative electrode material with a surface-connected binder as described above.

[0065] On the other hand, the present invention provides an electrochemical energy storage device, which includes the silicon-oxygen negative electrode material with a surface-connected binder as described above.

[0066] Preferably, the electrochemical energy storage device is selected from one of a lithium-ion battery, a sodium-ion battery, a supercapacitor, a fuel cell or a solar cell.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] In the present invention, by connecting a binder including a first polymer and a second polymer to the surface of the silicon-oxygen negative electrode material, it is possible to improve the swelling and aging problems of the silicon-oxygen negative electrode material during cycling, and at the same time, the adhesion between the silicon-oxygen negative electrode active substances and between the silicon-oxygen negative electrode active substances and the current collector can be improved, thereby enhancing the comprehensive performance of the material, and enabling the lithium-ion battery containing it to have a high initial Coulomb efficiency and cycle stability. Detailed implementation manners

[0069] The technical solution of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0070] Example 1

[0071] In this embodiment, a silicon-oxygen negative electrode material with a surface-connected binder is provided, and its preparation method includes the following steps:

[0072] (1) Place 800 g of an aqueous solution in which 5 g of polyvinyl alcohol (PVA) is dispersed in a 2000 L reaction kettle. Under a stirring state with a rotation speed of 250 rpm, introduce nitrogen with a purity ≥ 99.9%. Add the first polymerization monomers, including 100 g of methyl acrylate, 10 g of acrylamide monomer, and 10 g of acrylonitrile. Add 0.5 g of initiator AIBN, continuously stir, continuously introduce nitrogen, heat the solution to 75 °C, and carry out the first polymerization reaction for 5 hours to obtain a polymerization product. Reduce the pressure of the polymerization product with a vacuum pump to a vacuum degree lower than 0.1 MPa to remove the residual unreacted monomer components, and obtain the first polymer.

[0073] (2) Take 98 parts by weight of the silicon-oxygen negative electrode material (SiO, with a capacity of 1600 mAh / g) and 2 parts by weight of the first polymer, add a measured amount of deionized water to prepare a dispersion slurry with a solid content of 40%, and carry out mixing. Use a disperser at 800 rpm for 30 s and 2000 rpm for 10 min to make the slurry evenly dispersed. Remove the solvent moisture from the dispersed slurry by vacuum drying at room temperature to obtain a solvent-free mixture.

[0074] (3) Add 5 g of hexamethylene diisocyanate after water removal and 4 g of epoxyethane polymer with terminal hydroxyl groups (Tiantai Chemistry, TT310) into a mixing tank, and add 0.3 g of crosslinking agent 1,4-butanediol and 0.01 g of catalyst dibutyltin dilaurate. Under the condition of 2000 rpm in a defoaming machine, mix for 10 min to obtain a mixture. Take 1 part by weight of this mixture and 99 parts by weight of the solvent-free mixture obtained in step (2), and mix at 2000 rpm in a defoaming machine for 10 min. Then leave it at room temperature for 12 h for in-situ polymerization reaction until the binder is cured, and then grind the obtained product into fine powder in a mortar to obtain the silicon-oxygen negative electrode material with surface-connected binder.

[0075] Example 2

[0076] In this example, a silicon-oxygen negative electrode material with surface-connected binder is provided, and its preparation method includes the following steps:

[0077] (1) Place 800 g of an aqueous solution dispersing 5 g of polyvinyl alcohol PVA in a 2000 L reaction kettle. Under the stirring state with a rotation speed of 250 rpm, introduce nitrogen with a purity ≥ 99.9%. Add the first polymerization monomers, including 50 g of methyl acrylate, 10 g of acrylamide monomer, 20 g of acrylonitrile, and 10 g of styrene. Add 0.5 g of initiator AIBN, continuously stir, continuously introduce nitrogen, heat the solution to 80 °C, and carry out the first polymerization reaction for 8 h to obtain a polymerization product. Reduce the pressure of the polymerization product with a vacuum pump to a vacuum degree lower than 0.1 MPa to remove the residual unreacted monomer components to obtain the first polymer.

[0078] (2) Take 90 parts by weight of silicon-oxygen negative electrode material (SiO, capacity 1600 mAh / g) and 10 parts by weight of the first polymer, add a measured amount of deionized water to prepare a dispersion slurry with a solid content of 45%, and carry out mixing. Mix at 800 revolutions with a disperser for 30 s and at 2000 revolutions for 10 min to make the slurry uniformly dispersed. Remove the solvent water from the dispersed slurry by vacuum drying at room temperature to obtain a solvent-free mixture.

[0079] (3) Add 5 g of toluene diisocyanate after water removal and 4 g of epoxyethane polymer with terminal hydroxyl groups (Tiantai Chemistry, TT310) into a mixing tank, and add 0.3 g of crosslinking agent 1,4-butanediol and 0.02 g of catalyst dibutyltin dilaurate. Under the condition of 2000 rpm in a defoaming machine, mix for 10 min to obtain a mixture. Take 1 part by weight of this mixture and 99 parts by weight of the solvent-free mixture obtained in step (2), and mix at 2000 rpm in a defoaming machine for 10 min. Then leave it at room temperature for 12 h for reaction until the binder is cured, and then grind the obtained product into fine powder in a mortar to obtain the silicon-oxygen negative electrode material with surface-connected binder.

[0080] Example 3

[0081] In this embodiment, a silicon-oxygen negative electrode material with a surface-connected binder is provided, and its preparation method includes the following steps:

[0082] (1) Place 800 g of an aqueous solution in which 8 g of polyvinyl alcohol (PVA) is dispersed in a 2000 L reaction kettle. Under a stirring state with a rotation speed of 250 rpm, introduce nitrogen with a purity ≥ 99.9%. Add the first polymerization monomers, including 50 g of methyl acrylate, 20 g of acrylamide monomer, 10 g of acrylonitrile, and 5 g of styrene. Add 0.5 g of initiator AIBN, continuously stir, continuously introduce nitrogen, heat the solution to 80 °C, and carry out the first polymerization reaction for 10 hours to obtain a polymerization product. Use a vacuum pump to reduce the pressure of the polymerization product to a vacuum degree lower than 0.1 MPa to remove the remaining unreacted monomer components, and obtain the first polymer.

[0083] (2) Take 99 parts by weight of the silicon-oxygen negative electrode material (SiO, capacity 1600 mAh / g), 0.5 part by weight of the first polymer, and 0.5 part by weight of conductive carbon black. Add a measured amount of deionized water to prepare a dispersion slurry with a solid content of 40%. Carry out mixing, mix at 800 revolutions with a disperser for 30 s, and mix at 2000 revolutions for 10 min to make the slurry evenly dispersed. Remove the solvent moisture from the dispersed slurry through room-temperature vacuum drying to obtain a solvent-free mixture.

[0084] (3) Add 5 g of tetramethylxylylene diisocyanate after water removal and 4.5 g of hydroxyl-terminated ethylene oxide polymer (Tian Tai Chemistry, TT310) to a mixing tank together, and add 0.6 g of cross-linking agent 1,4-butanediol and 0.02 g of catalyst bismuth 2-ethylhexanoate. Under a state of 2000 rpm in a defoaming machine, mix for 10 min to obtain a mixture. Take 5 parts by weight of this mixture and 95 parts by weight of the solvent-free mixture obtained in step (2), and mix at 2000 rpm in a defoaming machine for 10 min. Then place it at room temperature for 24 h until the binder cures, and then grind the obtained product into a fine powder with a mortar to obtain the silicon-oxygen negative electrode material with a surface-connected binder.

[0085] Example 4

[0086] In this embodiment, a silicon-oxygen negative electrode material with a surface-connected binder is provided, and its preparation method includes the following steps:

[0087] (1) Place 800 g of an aqueous solution containing 2 g of polyvinyl alcohol (PVA) and 3 g of sodium dodecylbenzenesulfonate in a 2000 L reaction kettle. While stirring at a speed of 250 rpm, introduce nitrogen with a purity ≥ 99.9%. Add the first polymerization monomers, including 100 g of methyl acrylate, 10 g of acrylamide monomer, 10 g of acrylonitrile, and 10 g of styrene. Add 0.5 g of initiator AIBN. Continuously stir and continuously introduce nitrogen. Heat the solution to 95 °C and carry out the first polymerization reaction for 3 hours to obtain a polymerization product. Use a vacuum pump to reduce the pressure of the polymerization product to a vacuum degree below 0.1 MPa to remove the residual unreacted monomer components and obtain the first polymer.

[0088] (2) Take 90 parts by weight of silicon-oxygen anode material (SiO, capacity 1600 mAh / g), 8 parts by weight of the first polymer, and 2 parts by weight of conductive carbon black. Add a measured amount of deionized water to prepare a dispersion slurry with a solid content of 40%. Carry out mixing. Use a disperser to mix at 800 rpm for 30 s and at 2000 rpm for 10 min to make the slurry evenly dispersed. Remove the solvent moisture from the dispersed slurry by room-temperature vacuum drying to obtain a solvent-free mixture.

[0089] (3) Add 5.5 g of 4,4'-dicyclohexylmethane diisocyanate and 4.5 g of hydroxyl-terminated ethylene oxide polymer (Tian Tai Chemistry, TT310) after water removal to a mixing tank. Add 0.2 g of cross-linking agent 1,4-butanediol and 0.01 g of catalyst bismuth 2-ethylhexanoate. Mix at 2000 rpm in a defoaming machine for 10 min to obtain a mixture. Take 0.5 part by weight of this mixture and 99.5 parts by weight of the solvent-free mixture obtained in step (2). Mix at 2000 rpm in a defoaming machine for 10 min. Then let it stand at room temperature for 5 h until the binder cures. Then grind the obtained product into a fine powder with a mortar to obtain the silicon-oxygen anode material with a surface-connected binder.

[0090] Example 5

[0091] In this example, a silicon-oxygen anode material with a surface-connected binder is provided, and its preparation method includes the following steps:

[0092] (1) Place 800 g of an aqueous solution containing 2 g of polyvinyl alcohol (PVA) in a 2000 L reactor. While stirring at a speed of 250 rpm, introduce nitrogen with a purity of ≥99.9%. Add the first polymerization monomers, including 100 g of methyl acrylate, 10 g of acrylamide monomer, 10 g of acrylonitrile, and 10 g of styrene. Add 0.5 g of initiator AIBN. Continuously stir and continuously introduce nitrogen. Heat the solution to 50 °C and carry out the first polymerization reaction for 15 hours to obtain a polymerization product. Use a vacuum pump to reduce the pressure of the polymerization product to a vacuum degree of less than 0.1 MPa to remove the residual unreacted monomer components and obtain the first polymer.

[0093] (2) Take 99 parts by weight of silicon-oxygen anode material (SiO, capacity 1600 mAh / g), 0.5 part by weight of the first polymer, and 0.5 part by weight of conductive carbon black. Add a measured amount of deionized water to prepare a dispersion slurry with a solid content of 45%. Carry out mixing, using a disperser to mix at 800 rpm for 30 s and at 2000 rpm for 10 min to make the slurry evenly dispersed. Remove the solvent water from the dispersed slurry by vacuum drying at room temperature to obtain a solvent-free mixture.

[0094] (3) Add 4.5 g of isophorone diisocyanate after water removal and 5 g of hydroxyl-terminated ethylene oxide polymer (Tian Tai Chemistry, TT310) to a mixing tank together. Also add 0.8 g of crosslinking agent 1,4-butanediol and 0.02 g of catalyst bismuth 2-ethylhexanoate. Mix at 2000 rpm in a defoaming machine for 10 min to obtain a mixture. Take 10 parts by weight of this mixture and 90 parts by weight of the solvent-free mixture obtained in step (2), and mix at 2000 rpm in a defoaming machine for 10 min. Then place it at 40 °C for 30 h until the binder cures, and then grind the obtained product into a fine powder with a mortar to obtain the silicon-oxygen anode material with a surface-connected binder.

[0095] Example 6

[0096] In this example, a silicon-oxygen anode material with a surface-connected binder is provided, and its preparation method includes the following steps:

[0097] (1) Place 800 g of an aqueous solution containing 5 g of polyvinyl alcohol (PVA) in a 2000 L reactor. While stirring at a speed of 250 rpm, introduce nitrogen with a purity of ≥99.9%. Add the first polymerization monomers, including 80 g of methyl acrylate, 10 g of acrylamide monomer, 5 g of acrylonitrile, and 10 g of styrene. Add 0.5 g of initiator AIBN. Continuously stir and continuously introduce nitrogen. Heat the solution to 75 °C and carry out the first polymerization reaction for 8 hours to obtain a polymerization product. Use a vacuum pump to reduce the pressure of the polymerization product to a vacuum degree of less than 0.1 MPa to remove the residual unreacted monomer components and obtain the first polymer.

[0098] (2) Take 93 parts by weight of silicon oxide negative electrode material (SiO, capacity 1600 mAh / g), 2 parts by weight of the first polymer, and 5 parts by weight of conductive carbon black. Add a measured amount of deionized water to prepare a dispersion slurry with a solid content of 40%. Mix the materials. Use a disperser to mix at 800 revolutions for 30 s and then at 2000 revolutions for 10 min to make the slurry evenly dispersed. Remove the solvent moisture from the dispersed slurry by vacuum drying at room temperature to obtain a solvent-free mixture.

[0099] (3) Add 5.5 g of 1,5-naphthalene diisocyanate after water removal and 3.5 g of epoxyethane polymer with terminal hydroxyl groups (Tian Tai Chemistry, TT310) together into a mixing tank. Also add 0.4 g of cross-linking agent 1,4-butanediol and 0.01 g of catalyst bismuth 2-ethylhexanoate. Mix at 2000 rpm in a defoaming machine for 10 min to obtain a mixture. Take 10 parts by weight of this mixture and 90 parts by weight of the solvent-free mixture obtained in step (2), and mix at 2000 rpm in a defoaming machine for 10 min. Then place it at 100 °C for 5 h to react until the binder cures. Then grind the obtained product into a fine powder with a mortar to obtain the silicon oxide negative electrode material with the surface-connected binder.

[0100] Example 7

[0101] The difference from Example 1 is only that step (1) is as follows:

[0102] (1) Place 800 g of an aqueous solution in which 5 g of polyvinyl alcohol PVA is dispersed into a 2000 L reaction kettle. Under the stirring state with a rotation speed of 250 rpm, introduce nitrogen with a purity ≥ 99.9%. Add the first polymerization monomers, including 100 g of methyl acrylate, 10 g of acrylamide monomer, and 10 g of acrylonitrile. Add 0.5 g of cellulose acetate. Add 0.5 g of initiator AIBN. Continuously stir and continuously introduce nitrogen. Heat the solution to 75 °C and carry out the first polymerization reaction for 5 h to obtain a polymerization product. Reduce the pressure of the polymerization product with a vacuum pump to a vacuum degree lower than 0.1 MPa to remove the remaining unreacted monomer components to obtain the first polymer

[0103] Example 8

[0104] The difference from Example 7 is only that 5 g of carboxymethyl cellulose is used to replace cellulose acetate.

[0105] Example 9

[0106] The difference from Example 1 is only that in step (1), the first polymerization monomers only include 110 g of methyl acrylate and 10 g of acrylamide monomer.

[0107] Example 10

[0108] It is only different from Example 1 in that in step (1), the first polymerization monomer only includes 110 g of methyl acrylate and 10 g of acrylonitrile.

[0109] Example 11

[0110] It is only different from Example 1 in that in step (1), the first polymerization monomer only includes 110 g of methyl acrylate and 10 g of styrene.

[0111] Example 12

[0112] It is only different from Example 1 in that in step (1), the first polymerization monomer only includes 120 g of methyl acrylate.

[0113] Example 13

[0114] It is only different from Example 1 in that in step (1), the first polymerization monomer only includes 120 g of acrylamide monomer.

[0115] Example 14

[0116] It is only different from Example 1 in that in step (1), the first polymerization monomer only includes 120 g of styrene.

[0117] Example 15

[0118] It is only different from Example 1 in that in step (1), the first polymerization monomer only includes 120 g of acrylonitrile.

[0119] Comparative Example 1

[0120] It is only different from Example 1 in that in step (3), the hydroxyl-terminated ethylene oxide polymer is replaced with a hydroxyl-terminated acrylate polymer (Soken Chemical & Engineering Co., Ltd., UT-1001).

[0121] Comparative Example 2

[0122] It is only different from Example 1 in that in step (3), in-situ polymerization is not carried out, and the solvent-free mixture obtained in step (2) is directly used as the silicon-oxygen negative electrode material of the surface-connected binder.

[0123] Comparative Example 3

[0124] This comparative example provides a modified silicon-oxygen negative electrode material, and its preparation method is as follows:

[0125] 5 g of hexamethylene diisocyanate after water removal and 4 g of hydroxyl-terminated ethylene oxide polymer (Tian Tai Chemistry, TT310) were added together to a mixing tank, and 0.3 g of cross-linking agent 1,4-butanediol and 0.01 g of catalyst dibutyltin dilaurate were added. The mixture was mixed for 10 min at 2000 rpm in a defoaming machine to obtain a mixture. 1 part by weight of this mixture was taken and mixed with 99 parts by weight of silicon-oxygen anode material in a defoaming machine at 2000 rpm for 10 min. Then, it was left standing at room temperature for 12 h for in-situ polymerization reaction until the binder was cured, and then the obtained product was ground into a fine powder in a mortar to obtain the silicon-oxygen anode material with the surface-connected binder.

[0126] Application Examples 1-15 and Comparative Application Examples 1-3

[0127] The prepared silicon-oxygen anode material described above was made into an anode sheet. Specifically: the silicon-oxygen anode materials obtained in Examples 1-15 and Comparative Examples 1-3 were mixed with conductive agent carbon black (Surper P) and PAA binder in a mass ratio of 85:5:10 to obtain a slurry, and then coated onto a copper foil to form an anode sheet.

[0128] The prepared anode sheet was assembled with a lithium metal sheet into a lithium-ion button battery. LiPF6 was dissolved in an electrolyte of EC / DEC / EMC = 2:3:1 at a concentration of 1 mol / L. After the button battery assembly was completed, the following steps were carried out for the first Coulomb efficiency and cycle tests: standing for 2 h; constant current discharge: from 0.1C to 0.005V; from 0.08C to 0.001V; from 0.05C to 0.001V; from 0.02C to 0.001V; standing for 10 min; constant current charge: from 0.1C to 1.5V.

[0129] The results of the first Coulomb efficiency and cycle tests are shown in Table 1.

[0130] Table 1

[0131]

[0132]

[0133] It can be seen from the results in Table 1 that the silicon-oxygen anode material with the surface-connected binder of the present invention can make the first Coulomb efficiency of the battery using it reach more than 87%, and the capacity retention rate after 1000 cycles reach more than 80%, having good first Coulomb efficiency and cycle stability of the battery.

[0134] In Comparative Example 1, since the hydroxyl-terminated ethylene oxide polymer in the second polymer was replaced with a hydroxyl-terminated acrylate polymer, the interaction force between the acrylate and the surface functional groups of the silicon-oxygen material was weaker than that of ethylene oxide, resulting in a decrease in the first Coulomb efficiency and cycle stability of its battery.

[0135] In Comparative Example 2, in-situ polymerization in step (3) was not carried out, so that the binder in the silicon-oxygen negative electrode material with surface-connected binder obtained only included the first polymer, and a good polymer coating network structure could not be formed, resulting in a decrease in the initial Coulombic efficiency of the battery and a decrease in the cycle stability at the same time.

[0136] In the silicon-oxygen negative electrode material with surface-connected binder obtained in Comparative Example 3, the binder only included the second polymer, and a good polymer coating network structure could not be formed, resulting in a decrease in the initial Coulombic efficiency of the battery and a decrease in the cycle stability at the same time.

[0137] The applicant declares that the present invention uses the above embodiments to illustrate the silicon-oxygen negative electrode material with surface-connected binder, its preparation method and the battery of the present invention, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A silicon-oxygen negative electrode material with a surface-connected binder, characterized in that, The silicon-oxygen anode material with a surface-connected binder includes a silicon-oxygen anode material and a binder connected to its surface. The binder includes a first polymer and a second polymer. The polymerization monomers of the first polymer include any one or a combination of at least two of acrylate monomers, acrylamide monomers, acrylonitrile monomers, or styrene monomers. The polymerization monomers of the second polymer include isocyanate monomers and an ethylene oxide polymer containing terminal hydroxyl groups; The functional groups contained in the ethylene oxide polymer form chemical bonds with the active groups on the surface of the silicon-oxygen anode material; The first polymer is in a particle structure, and the second polymer is in a non-particle structure. The first polymer and the second polymer form a polymer network on the surface of the silicon-oxygen anode material; The second polymer is obtained by in-situ polymerization on the surface of the silicon-oxygen anode material connected with the first polymer.

2. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that The silicon-oxygen anode material is a silicon-based oxide anode material SiOx, where x is 0 - 2, but does not include 0.

3. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that, The acrylate monomers are selected from any one or a combination of at least two of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, sodium acrylate, lithium acrylate, acrylic acid, lithium methacrylate, methacrylic acid, lithium itaconate, itaconic acid, lithium itaconate monobutyl ester, or itaconic acid monobutyl ester.

4. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that, The acrylamide monomers are selected from any one or a combination of at least two of acrylamide, methacrylamide, N-hydroxymethylacrylamide, or N,N-dimethylacrylamide.

5. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that The binder further includes cellulose; the cellulose is mixed with the first polymer.

6. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 5, characterized in that The cellulose is selected from any one or a combination of at least two of cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, nitrocellulose, carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose, sodium cellulose, sodium nitrocellulose, or carboxyalkyl cellulose sodium.

7. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that The isocyanate monomers are selected from any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2,2,4-trimethylhexane diisocyanate, phthalic diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, or norbornane diisocyanate.

8. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that, The hydroxyl-terminated ethylene oxide polymer is a liquid hydroxyl-terminated ethylene oxide polymer, and the number average molecular weight of the hydroxyl-terminated ethylene oxide polymer is 100-10,000.

9. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that The glass transition temperature Tg of the first polymer ranges from -50 to 200 °C.

10. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that, The particle size of the first polymer is 200 nm - 10 μm.

11. The silicon-oxygen negative electrode material of the surface-connected binder according to claim 1, characterized in that, The first polymer is polymerized by emulsion polymerization, microemulsion polymerization, suspension polymerization or minisuspension polymerization methods.

12. The preparation method of the silicon-oxygen negative electrode material of the surface-connected binder according to any one of claims 1-11, characterized in that, The preparation method includes the following steps: (1) The first polymer and the silicon-oxygen anode material are added to a solvent for wet mixing to obtain a mixed slurry, and then the solvent in the mixed slurry is removed to obtain a solvent-free mixture; (2) The isocyanate monomer, the hydroxyl-terminated ethylene oxide polymer, the crosslinking agent and the catalyst are mixed, and then mixed with the solvent-free mixture obtained in step (1) to carry out an in-situ polymerization reaction to obtain the silicon-oxygen anode material with the surface-connected binder.

13. The preparation method according to claim 12, characterized in that, The preparation method of the first polymer in step (1) includes the following steps: The first polymerization monomer and the initiator are added to an aqueous solution containing an emulsifier and / or a dispersant for the first polymerization reaction to obtain a first polymer emulsion. The solvent water in the obtained binder emulsion is removed to obtain the first polymer. The first polymerization monomer includes any one or at least two combinations of acrylate monomers, acrylamide monomers, acrylonitrile monomers or styrene monomers.

14. The preparation method according to claim 13, characterized in that, Based on the total weight of the emulsifier, the dispersant, the first polymerization monomer and the initiator being 100%, the total proportion of the dispersant and the emulsifier is 0.1% - 20.0%, the proportion of the first polymerization monomer is 60.0% - 99.8%, and the proportion of the initiator is 0.1% - 10.0%.

15. The preparation method according to claim 13, wherein The total weight percentage of the emulsifier, the dispersant, the first polymerization monomer and the initiator in the first polymer emulsion is 2% - 30%.

16. The preparation method according to claim 13, characterized in that, The acrylate monomers are selected from any one or at least two combinations of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, sodium acrylate, lithium acrylate, acrylic acid, lithium methacrylate, methacrylic acid, lithium itaconate, itaconic acid, lithium itaconate monobutyl ester or itaconic acid monobutyl ester.

17. The preparation method according to claim 13, characterized in that, The acrylamide monomers are selected from any one or at least two combinations of acrylamide, methacrylamide, N-hydroxymethylacrylamide or N,N-dimethylacrylamide.

18. The preparation method according to claim 13, characterized in that, Cellulose is also added to the system of the first polymerization reaction.

19. The preparation method according to claim 18, characterized in that, The cellulose is selected from any one or a combination of at least two of cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, nitrocellulose, carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose, sodium cellulose, sodium nitrocellulose or sodium carboxyalkyl cellulose.

20. The preparation method according to claim 18, characterized in that, The dosage of the cellulose is 0.1% - 5.0% of the total weight of the first polymerization monomer.

21. The preparation method according to claim 13, characterized in that, The emulsifier is one or a combination of at least two of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate or sodium dodecyl sulfonate.

22. The preparation method according to claim 13, wherein, The dispersant is one or a combination of at least two of polyvinyl alcohol, polyvinylpyrrolidone, tetradecane, hexadecane or octadecane.

23. The preparation method according to claim 13, characterized in that, The initiator is independently an organic peroxide initiator, an organic azo initiator, an inorganic peroxide initiator or a redox initiator.

24. The preparation method according to claim 23, wherein The organic peroxide initiator is benzoyl peroxide or dicumyl peroxide.

25. The preparation method according to claim 23, characterized in that, The organic azo initiator is azobisisobutyronitrile or azobisisoheptonitrile.

26. The preparation method according to claim 23, wherein, The inorganic peroxide initiator is ammonium persulfate, sodium persulfate or potassium persulfate.

27. The preparation method according to claim 23, characterized in that, The redox initiator is ammonium persulfate and sodium sulfite, or ammonium persulfate and sodium bisulfite.

28. The preparation method according to claim 13, characterized in that, The temperature of the first polymerization reaction is 35 - 98 °C.

29. The preparation method according to claim 13, characterized in that, The time of the first polymerization reaction is 3 - 15 h.

30. The preparation method according to claim 12, characterized in that, In the mixed slurry in step (1), based on the total weight of the first polymer and the silicon-oxygen anode material being 100%, the proportion of the first polymer is 0.5 - 10.0%, and the proportion of the silicon-oxygen anode material is 90.0 - 99.5%.

31. The preparation method according to claim 12, wherein, The mixed slurry in step (1) further includes a conductive additive.

32. The preparation method according to claim 31, characterized in that, The conductive additive includes one or a combination of at least two of conductive graphite, acetylene black, carbon nanotubes or conductive carbon black.

33. The preparation method according to claim 31, wherein, In the mixed slurry in step (1), based on the total weight of the first polymer and the silicon-oxygen anode material being 100%, the proportion of the conductive additive is 0 - 5%.

34. The preparation method according to claim 12, characterized in that, The wet mixing process in step (1) includes a resonance acoustic mixing process, a high-shear process and a grinding process.

35. The preparation method according to claim 12, characterized in that, The wet mixing operation in step (1) includes using one or a combination of at least two of a ball mill, an electromagnetic ball mill, a disc mill, a pin-bar mill, a high-energy impact mill, a fluid energy impact mill, a jet mill, a fluidized bed jet mill, a hammer mill or an impact mill.

36. The preparation method according to claim 12, wherein, The method for removing the solvent from the mixed slurry in step (1) is any one or a combination of at least two of vacuum drying, centrifugation, freeze drying, spray drying.

37. The preparation method according to claim 12, wherein The total weight of the isocyanate monomer and the epoxyethane polymer containing terminal hydroxyl groups in step (2) is 0.1% - 10.0% of the weight of the solvent-free mixture.

38. The preparation method according to claim 12, characterized in that, The weight ratio of the isocyanate monomer and the epoxyethane polymer containing terminal hydroxyl groups in step (2) is 1:2 - 5:

1.

39. The preparation method according to claim 12, wherein The dosage of the crosslinking agent in step (2) is 0.1% - 10.0% of the total weight of the isocyanate monomer and the epoxyethane polymer containing terminal hydroxyl groups.

40. The preparation method according to claim 12, characterized in that, The dosage of the catalyst in step (2) is 0.1% - 5.0% of the total weight of the isocyanate monomer and the epoxyethane polymer containing terminal hydroxyl groups.

41. The preparation method according to claim 12, wherein The isocyanate monomer described in step (2) is selected from any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2,2,4-trimethylhexane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, or norbornane diisocyanate.

42. The preparation method according to claim 12, characterized in that, The epoxyethane polymer containing terminal hydroxyl groups is a liquid epoxyethane polymer containing terminal hydroxyl groups, and the number-average molecular weight of the epoxyethane polymer containing terminal hydroxyl groups is 100 - 10,000.

43. The preparation method according to claim 12, characterized in that, The crosslinking agent described in step (2) is selected from any one or a combination of at least two of diol crosslinking agents, triol crosslinking agents, diamine crosslinking agents, alkanolamine crosslinking agents, alicyclic alcohol crosslinking agents, aromatic alcohol crosslinking agents, allyl glycidyl ether, glycerol allyl ether, or dicumyl peroxide.

44. The preparation method according to claim 43, characterized in that, The crosslinking agent described in step (2) is selected from any one or a combination of at least two of 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, glycerol, trimethylolpropane, 3,3-dichloro-4,4-diaminodiphenylmethane, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine, 2,4-diamino-3,5-dimethylthiobenzene chloride, isophorone diamine, ethanolamine, diethanolamine, triethanolamine, N,N-bis(2-hydroxypropyl)aniline, 1,4-cyclohexanediol, hydrogenated bisphenol A, dimethylenephenyl glycol, hydroquinone bis-β-hydroxyethyl ether, resorcinol hydroxy ether, glycerol allyl ether, allyl glycidyl ether, or dicumyl peroxide.

45. The preparation method according to claim 12, characterized in that, The catalyst described in step (2) is selected from any one or a combination of at least two of tertiary amine catalysts or organometallic compounds.

46. The preparation method according to claim 45, characterized in that, The catalyst described in step (2) is selected from any one or a combination of at least two of N,N-dimethylcyclohexylamine, dibutyltin dilaurate, bismuth 2-ethylhexanoate, or bismuth neodecanoate.

47. The preparation method according to claim 12, characterized in that, The temperature of the in-situ polymerization reaction described in step (2) is 25 - 100 °C.

48. The preparation method according to claim 12, characterized in that, The time of the in-situ polymerization reaction described in step (2) is 5 - 50 h.

49. A negative electrode sheet, characterized in that, The negative electrode sheet includes the silicon-oxygen negative electrode material with a surface-connected binder as described in any one of claims 1 - 11.

50. An electrochemical energy storage device, characterized in that, The electrochemical energy storage device includes the silicon-oxygen negative electrode material with a surface-connected binder as described in any one of claims 1 - 11.

51. The electrochemical energy storage device according to claim 50, characterized in that, The electrochemical energy storage device is selected from one of lithium-ion batteries, sodium-ion batteries, supercapacitors, fuel cells, or solar cells.

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