Silicon-based negative plate, preparation method thereof and battery

Abstract

The invention relates to the technical field of batteries, in particular to a silicon-based negative plate, a preparation method thereof and a battery. The silicon-based negative plate comprises a current collector; the active layer is arranged on the surface of at least one side of the current collector in the thickness direction, and the active layer comprises an active material, a binding phase and a conductive agent; wherein the active material comprises a carbon-based active material and a silane coupling agent modified silicon-based active material; the binding phase comprises a three-dimensional network structure formed by epoxy-amine. According to the silicon-based negative plate, on the premise that the system complexity is not increased, through the synergistic effect of interface chemical bonding and a binding phase toughness network, three-dimensional inhibition of the volume effect of a silicon-based material, precise regulation and control of technological parameters and long-term stability of an electrode structure and a conductive network are synchronously achieved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a silicon-based negative electrode sheet, its preparation method, and a battery. Background Technology

[0002] Silicon-based anodes, with their theoretical specific capacity of approximately 4200 mAh / g, are considered core candidate materials for high-energy-density lithium-ion batteries. However, the volume expansion and contraction of up to 300% during lithium insertion / extraction leads to electrode sheet expansion, active material particle cracking, and interface detachment, resulting in increased interfacial impedance, intensified electrolyte side reactions, and rapid capacity decay, severely limiting their practical application. Currently, commonly used binder solutions in aqueous systems (such as styrene-butadiene rubber (SBR) / carboxymethyl cellulose (CMC) physical blends or polyacrylic acid (PAA)-based systems) are insufficient to effectively address these issues. While the SBR / CMC system is low-cost and has mature technology, it suffers from problems such as SBR floating after drying, leading to insufficient interfacial shear strength, and CMC premature curing and poor dispersibility due to its high viscosity; under high compaction, its brittleness further exacerbates electrode structural failure. While PAA-type binders enhance interfacial stability by forming hydrogen / covalent bonds between carboxyl groups and the silicon surface, their single function makes it difficult to simultaneously achieve high bond strength and flexibility. Salt-type or copolymer modification suffers from poor batch stability and difficulty in parameter quantification due to complex multi-component mixing and narrow process windows. To mitigate the volume expansion effect, existing technologies attempt to enhance electrode stability through bilayer coating structures or loading with highly conductive agents (such as carbon nanotubes, CNTs). However, bilayer coatings require additional process steps and carry a high risk of interlayer stress concentration, while loading with highly conductive agents reduces compaction density, exacerbating the contradiction between ion transport and energy density. Simultaneously, uneven dispersion or agglomeration of CNTs leads to discontinuous conductive networks, making the framework prone to breakage under high compaction, further deteriorating cycling performance.

[0003] In summary, existing technologies suffer from systemic deficiencies in areas such as interfacial chemical anchoring capability, bulk stress buffering function, process compatibility, and parameter traceability. Therefore, there is an urgent need to provide a three-dimensional composite bonding system that, without increasing system complexity, achieves simultaneous three-dimensional suppression of volume effects in silicon-based materials, precise control of process parameters, and long-term stability of the electrode structure and conductive network through the synergistic effect of interfacial chemical bonding and the toughness network of the binder phase. Summary of the Invention

[0004] In view of this, the present invention aims to at least partially solve one of the technical problems in the related art. To this end, the present invention provides a silicon-based anode sheet, its preparation method, and a battery. This silicon-based anode sheet, without increasing the complexity of the system, simultaneously achieves three-dimensional suppression of the volume effect of silicon-based materials, precise control of process parameters, and long-term stability of the electrode structure and conductive network through the synergistic effect of interfacial chemical bonding and the toughness network of the binder phase.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows: According to one aspect of this application, an embodiment of this application provides a silicon-based negative electrode, the silicon-based negative electrode comprising: current collector; An active layer is disposed on at least one side surface of the current collector along the thickness direction, and the active layer includes an active material, a binder phase, and a conductive agent; The active materials include carbon-based active materials and silicon-based active materials modified with silane coupling agents; The binder phase comprises a three-dimensional network structure composed of epoxy-amine.

[0006] In some embodiments, the binder phase is prepared from an epoxy resin and an amine curing agent.

[0007] In some embodiments, the epoxy equivalent in the epoxy resin is 450~900 g / eq; the amine hydrogen equivalent in the amine curing agent is 90~350 g / eq; and when preparing the binder phase, the ratio of the epoxy equivalent in the epoxy resin to the amine hydrogen equivalent in the amine curing agent is controlled to be 0.8~1.1.

[0008] In some of these embodiments, the silane coupling agent modified silicon-based active material has the silane coupling agent loaded on at least a portion of the surface of the silicon-based active material.

[0009] In some embodiments, the silane coupling agent loading is defined as the percentage of the silane coupling agent by mass of the silicon-based active material, and the silane coupling agent loading is 0.3% to 2%.

[0010] In some of these embodiments, the silane coupling agent comprises at least one of 3-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and isocyanate propyltriethoxysilane.

[0011] In some of these embodiments, the silicon-based active material includes at least one of silicon-carbon composite materials, elemental silicon, silicon oxide, and porous silicon.

[0012] In some embodiments, the average particle size Dv50 of the silicon-based active material is 0.1~10 μm.

[0013] In some of these embodiments, the mass ratio of the carbon-based active material to the silane coupling agent-modified silicon-based active material is (70~90):(10~30).

[0014] In some embodiments, the carbon-based active material includes at least one of graphite, soft carbon, hard carbon, and mesophase carbon microspheres.

[0015] In some embodiments, the conductive agent includes at least one of vapor-grown carbon fibers and graphene.

[0016] In some embodiments, the conductive agent is selected from a mixture of vapor-grown carbon fibers and graphene, wherein the mass ratio of the vapor-grown carbon fibers to graphene is 1:(0.2~1).

[0017] In some of these embodiments, the mass ratio of the active material, the binder phase, and the conductive agent is 100:(2~8):(0.5~6).

[0018] According to another aspect of this application, embodiments of this application provide a method for preparing a silicon-based negative electrode, comprising the following steps: The active material, binder, and conductive agent are mixed in a solvent to obtain an active slurry. The active slurry is coated onto at least one side of the current collector, and after curing and rolling, a silicon-based negative electrode sheet is obtained. The adhesive includes epoxy resin and amine curing agent; The active materials include carbon-based active materials and silicon-based active materials modified with silane coupling agents.

[0019] In some embodiments, the preparation method of the silane coupling agent modified silicon-based active material includes at least one of wet acid catalysis, wet alkaline catalysis, and gas-phase silanization.

[0020] In some embodiments, the method for preparing the silane coupling agent modified silicon-based active material is preferably a wet acid catalytic method, comprising the following steps: Silicon-based active materials are modified by mixing them with a solution containing a silane coupling agent to obtain silane coupling agent-modified silicon-based active materials.

[0021] In some embodiments, the pH value of the modification treatment is 4.5 to 5.5, and the time is 0.5 to 3 hours.

[0022] In some embodiments, the curing is carried out under an inert atmosphere at a temperature of 90-120°C for a time of 20-60 minutes.

[0023] In some embodiments, the compaction density of the roller press is 1.2~1.7 g / cm³. 3 .

[0024] According to another aspect of this application, an embodiment of this application provides a battery including a negative electrode sheet, wherein the negative electrode sheet is the aforementioned silicon-based negative electrode sheet or a silicon-based negative electrode sheet prepared according to the aforementioned preparation method.

[0025] Implementing the technical solution of the present invention has at least the following beneficial effects: In this embodiment, the silicon-based active material provided is a silane coupling agent-modified silicon-based active material. The silane coupling agent is loaded on the surface of the silicon-based active material and anchors it to the three-dimensional network structure binder phase composed of epoxy-amine through covalent bonds. Conventional active materials and binders mainly rely on physical adsorption and mechanical interlocking, resulting in reduced interfacial shear strength. During cyclic expansion and contraction, microcracks, pulverization, and localized debonding are more likely to occur, leading to poor current distribution and inducing repeated SEI rupture. Peel strength and capacity decrease synchronously, and expansion suppression capability is significantly weakened. The solution of this application can significantly improve interfacial shear strength and cycle stability, effectively solving the defects of the prior art and thus improving battery performance.

[0026] Therefore, the silicon-based anode sheet of this application, by improving the binder phase structure and silicon-based active material, achieves three-dimensional suppression of the volume effect of silicon-based materials and precise control of process parameters simultaneously through the synergistic effect of interfacial chemical bonding and bulk toughness network, without increasing the complexity of the system. This results in a more stable structure and cycle stability for the silicon-based anode sheet, and a longer lifespan and superior electrical performance for batteries containing this silicon-based anode sheet.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0028] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0029] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges or individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0031] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0032] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0033] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0034] To mitigate the volume expansion effect of silicon-based anode sheets, existing technologies attempt to enhance electrode stability through double-layer coating structures or loading with highly conductive agents (such as carbon nanotubes, CNTs). However, double-layer coating requires additional process steps and carries a high risk of stress concentration between layers, while loading with highly conductive agents reduces compaction density, exacerbating the contradiction between ion transport and energy density. At the same time, uneven dispersion or agglomeration of CNTs leads to discontinuous conductive networks, and the framework is prone to breakage under high compaction, further deteriorating cycle performance.

[0035] In view of this, embodiments of this application provide a silicon-based anode sheet, the silicon-based anode sheet comprising: current collector; An active layer is disposed on at least one side surface of the current collector along the thickness direction, and the active layer includes an active material, a binder phase, and a conductive agent; The active materials include carbon-based active materials and silicon-based active materials modified with silane coupling agents; The binder phase comprises a three-dimensional network structure composed of epoxy-amine.

[0036] The phrase "the active layer is disposed on at least one surface of the current collector along its thickness direction" means that the active layer can be disposed on one surface of the current collector along its own thickness direction, or on two surfaces of the current collector along its own thickness direction. Here, "surface" can be the entire area of ​​the current collector or a part of the current collector. As in this embodiment, the surface can be the entire area of ​​the current collector. This application does not have any particular limitation in this regard, as long as the purpose of this application can be achieved.

[0037] As an example, the current collector has two surfaces opposite each other in its own thickness direction, and the active layer is disposed on the two opposite surfaces of the current collector. It is understood that in other embodiments, the active layer may also be stacked on either of the two surfaces of the current collector 1.

[0038] In this application, the material of the current collector in the silicon-based anode is not specifically limited.

[0039] In this application, the binder phase in the active layer of the silicon-based negative electrode is obtained by curing epoxy resin with an amine curing agent. Specifically, the primary amine undergoes ring opening to generate a β-hydroxy secondary amine, with the chemical formula: R–NH2+ (epoxy)–R'→R–NH–CH2–CH(OH)–R'; then the secondary amine continues to undergo ring opening to generate a β-hydroxy quaternary amine (crosslinking point), with the chemical formula: R–NH–R'' + (epoxy)–R'→R–N(R'')–CH2–CH(OH)–R'. This can be understood as the primary amine (R–NH2) attacking the epoxy groups of the epoxy resin to open the ring, yielding a β-hydroxy secondary amine (R–NH–CH2–CH(OH)–R'). The β-hydroxy secondary amine then attacks other epoxy groups in the epoxy resin or other epoxy groups in other epoxy resins to generate a β-hydroxy quaternary amine. The β-hydroxy quaternary amine sites act as three-dimensional crosslinking nodes, ultimately resulting in a three-dimensional network structure composed of epoxy and amine in the binder phase of the active layer. Wherein, R is selected from straight chains or branched chains C1–C. 12 Aliphatic, C3–C8 cyclic aliphatic, C6–C 15 Aromatic groups, or polyether segments —(CH2—CH2—O) n —、—(CH2—CH(CH3)—O) n —, n is an integer from 2 to 200. R' is an organic group of the epoxy resin molecular backbone, selected from the aromatic ring, cycloalkane ring, or alkyl framework corresponding to the bisphenol A / F type, phenolic type, cycloaliphatic or aliphatic epoxy residues, and may contain —O— or —C(CH3)2— linker groups. R'' is another organic group attached to nitrogen on the secondary amine, preferably —CH2—CH(OH)—R' introduced by the first ring-opening step; or an aliphatic, cycloaliphatic, aromatic or polyether segment carried by the starting diamine molecule.

[0040] In this application, the silicon-based active material is a silane coupling agent-modified silicon-based active material. The silane coupling agent is loaded on the surface of the silicon-based active material and anchors it to the three-dimensional network structure binder phase composed of epoxy-amine through covalent bonds. Conventional active materials and binders rely mainly on physical adsorption and mechanical intercalation, resulting in reduced interfacial shear strength. During cyclic expansion and contraction, microcracks, pulverization, and localized debonding are more likely to occur, leading to poor current distribution and inducing repeated SEI rupture. Peel strength and capacity decrease synchronously, and expansion suppression capability is significantly weakened. The solution in this application can significantly improve interfacial shear strength and cycle stability, effectively addressing the shortcomings of existing technologies and thus improving battery performance.

[0041] Therefore, the silicon-based anode sheet of this application, by improving the binder phase structure and silicon-based active material, achieves three-dimensional suppression of the volume effect of silicon-based materials and precise control of process parameters simultaneously through the synergistic effect of interfacial chemical bonding and bulk toughness network, without increasing the complexity of the system. This results in a more stable structure and cycle stability for the silicon-based anode sheet, and a longer lifespan and superior electrical performance for batteries containing this silicon-based anode sheet.

[0042] In some embodiments, the binder phase is prepared from epoxy resin and amine curing agent.

[0043] In some embodiments, the epoxy equivalent in the epoxy resin is 450~900 g / eq; the amine hydrogen equivalent in the amine curing agent is 90~350 g / eq; and the ratio of epoxy equivalent to amine hydrogen equivalent in the binder phase is 0.8~1.1. It should be noted that epoxy equivalent refers to the mass of epoxy resin corresponding to each epoxy group; amine hydrogen equivalent refers to the mass of amine curing agent corresponding to each active hydrogen (ring-opening epoxy group).

[0044] For example, the epoxy equivalent in the epoxy resin can be 450 g / eq, 550 g / eq, 650 g / eq, 750 g / eq, 850 g / eq, 900 g / eq, etc., or any value within the above range; no specific limitation is made here. Controlling the epoxy equivalent in the epoxy resin within the above range can, while maintaining one-time medium-temperature curing, impart an appropriate functional group density and crosslinking degree to the binder phase, improve interfacial shear strength and dimensional stability, avoid embrittlement and shrinkage caused by excessively dense functional groups, and also avoid creep and insufficient adhesion caused by excessively sparse functional groups, thereby facilitating the achievement of higher peel strength and long-term cycle retention.

[0045] For example, the amine hydrogen equivalent in amine curing agents can be 90 g / eq, 150 g / eq, 200 g / eq, 250 g / eq, 300 g / eq, 350 g / eq, etc., or any value within the above range; no specific limitation is made here. Controlling the amine hydrogen equivalent in amine curing agents within the above range can ensure equal-volume reaction of active hydrogen and controlled curing rate, while also taking into account network toughness and creep resistance, reducing residual functional groups and the risk of local over-curing, thereby improving the adhesion, dimensional stability, and long-cycle performance of the electrode.

[0046] Meanwhile, when preparing the binder phase, the ratio of epoxy equivalent in the epoxy resin to amine hydrogen equivalent in the amine curing agent is controlled to be 0.8~1.1. A uniform and dense three-dimensional network can be obtained near this stoichiometry, reducing liquid absorption, softening or embrittlement problems caused by residual functional groups, thereby further improving adhesion and cycle stability.

[0047] Furthermore, the ratio of epoxy equivalent in the epoxy resin to amine hydrogen equivalent in the amine curing agent directly determines the effective crosslinking density of the binder phase. If the ratio is too low, there is an excess of active hydrogen, and unreacted epoxy groups coexist with loose chain segments. During battery cycling, the coating undergoes viscoelastic creep and stress relaxation, resulting in significantly poorer interfacial adhesion and structural stability, and an increased expansion rate. If the ratio is too high, there is a relative excess of epoxy groups, making the three-dimensional network structure of the binder phase harder and more brittle. Local etherified or unconverted epoxy group residues appear, reducing the crack propagation threshold and leading to a decrease in the long cycle life of the silicon-based anode sheet.

[0048] In some embodiments, in the silane coupling agent modified silicon-based active material, the silane coupling agent is loaded on at least a portion of the surface of the silicon-based active material.

[0049] In some embodiments, the silane coupling agent loading is defined as the percentage of the silane coupling agent by mass of the silicon-based active material, and the silane coupling agent loading is 0.3% to 2%. As an example, the silane coupling agent loading can be 0.3%, 0.8%, 1.3%, 1.8%, 2%, etc., by mass of the silicon-based active material, or any value within the above range; no specific limitation is made here. The silane coupling agent loading determines the density of covalent anchoring sites and the interfacial energy on the surface of the silicon-based active material; and by providing reactive end groups, it chemically reacts with the epoxy-amine curing network to form effective connection points in the interfacial layer, improving the interfacial shear strength and dimensional stability. This process does not change the crosslinking density of the bulk binder phase, which is controlled by the epoxy / amine equivalent ratio and the curing process. If the silane coupling agent loading is too low, the silicon-based active material mainly relies on physical adsorption and mechanical intercalation, resulting in reduced interfacial shear strength. During cyclic expansion and contraction, microcracks, pulverization, and localized debonding are more likely to occur, leading to poor current distribution and inducing repeated SEI rupture. Peel strength and capacity decrease synchronously, and the expansion suppression capability is significantly weakened. If the silane coupling agent loading is too high, the degree of interfacial densification is improved, which is beneficial for suppressing particle displacement of the silicon-based active material. However, excessively high interfacial densification increases the resistance to cross-interfacial electron and ion migration, ultimately adversely affecting the battery's rate capability and long-term cycling performance.

[0050] In some embodiments, the silane coupling agent includes at least one of 3-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and isocyanate propyltriethoxysilane. As an example, the silane coupling agent may be 3-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane.

[0051] In some embodiments, the silicon-based active material includes at least one of silicon-carbon composite material, elemental silicon, silicon oxide, and porous silicon. As an example, the silicon-based active material may be a silicon-carbon composite material, elemental silicon, or silicon oxide.

[0052] In some embodiments, the average particle size Dv50 of the silicon-based active material is 0.1~10μm. As an example, the average particle size Dv50 of the silicon-based active material can be 0.1μm, 1μm, 3μm, 5μm, 8μm, 10μm, etc., or it can be any value within the above range, and no specific limitation is made here.

[0053] In some embodiments, the mass ratio of the carbon-based active material to the silane coupling agent-modified silicon-based active material is (70~90):(10~30). As an example, the mass ratio of the carbon-based active material to the silane coupling agent-modified silicon-based active material can be 70:30, 80:20, 90:10, etc., or any ratio within the above range; no specific limitation is made here. The mass proportion of the silane coupling agent-modified silicon-based active material directly affects the specific capacity and volume expansion of the battery. Limiting the mass ratio of the carbon-based active material to the silane coupling agent-modified silicon-based active material within the above range, combined with the silane coupling agent-modified silicon-based active material and the metering curing scheme of this application, can enable the battery to have higher energy density and longer cycle life. If the ratio of the two is too low, the proportion of silane coupling agent-modified silicon-based active material is too large. Although this can improve the reversible capacity of the battery, the large volume change of silicon during lithium insertion and extraction makes it difficult for the silane coupling agent-modified silicon-based active material to be completely anchored on the three-dimensional network of the binder phase. At the same time, the buffering capacity of the three-dimensional network of the binder phase is also insufficient to cope with the volume expansion of silicon. During cycling, fresh exposed surfaces are easily generated, and the SEI is repeatedly formed and damaged, leading to an increase in expansion rate and a decrease in capacity. If the ratio of the two is too large, the proportion of silane coupling agent-modified silicon-based active material is too small. This can significantly reduce volume stress and the probability of interface damage, and adhesion and dimensional stability are easier to meet, but it will result in a low specific capacity of the battery.

[0054] In some embodiments, the carbon-based active material includes at least one of graphite, soft carbon, hard carbon, and mesophase carbon microspheres. As an example, the carbon-based active material can be graphite, soft carbon, or hard carbon.

[0055] In some embodiments, the conductive agent includes at least one of vapor-grown carbon fiber and graphene. As an example, the conductive agent may be vapor-grown carbon fiber or graphene.

[0056] In some embodiments, the conductive agent is selected from a mixture of vapor-grown carbon fibers and graphene, wherein the mass ratio of vapor-grown carbon fibers to graphene is 1:(0.2~1). As an example, the mass ratio of vapor-grown carbon fibers to graphene can be 1:0.2, 1:0.5, 1:1, etc., or any ratio within the above range; no specific limitation is made here. Therefore, vapor-grown carbon fibers and graphene can synergistically construct long- and short-range electron channels, eliminating the need for carbon nanotubes. A highly efficient conductive framework can be formed with a smaller amount of these materials, while reducing shear damage to the binder phase and balancing the percolation threshold and pore connectivity of the active layer of the silicon-based anode sheet.

[0057] In some embodiments, the mass ratio of the active material, binder phase, and conductive agent is 100:(2~8):(0.5~6). As examples, the mass ratio of the active material, binder phase, and conductive agent can be 100:2:0.5, 100:5:3, 100:8:6, etc., or any ratio within the above range; no specific limitation is made here. Controlling the proportion of the binder phase within the above range allows for good continuity of the active layer film during the preparation of the silicon-based negative electrode, ensuring good wetting effect and energy dissipation capacity (i.e., the ability to transfer expansion-contraction stress during the cycling process of the negative electrode). Simultaneously, the binder phase is permeable and tough within the active layer, enhancing the adhesion of the active layer and coping with the volume expansion of silicon. If the proportion of the binder phase is too low, the pore walls will not be completely coated, resulting in point contact between particles, uneven load transfer, increased local current density, and side reactions. The SEI is prone to repeated breakage, manifested as a significant decrease in peel strength and accelerated cycle decay. If the proportion of the binder phase is too high, although adhesion and swelling suppression will be slightly improved, the reduced non-porous connectivity will increase ion diffusion paths, increase intra-sheet polarization, and maintain a decrease in capacity.

[0058] Furthermore, controlling the content of the conductive agent within the aforementioned range allows for higher electron flow in the silicon-based anode sheet and a more uniform current distribution. If the proportion of the conductive agent is too low, the conductive network in the active layer will not reach the flow threshold, resulting in a significant increase in sheet resistance, increased battery polarization, a rise in local overpotential, more pronounced side reactions and SEI thickening, and a significant decrease in cycle retention. If the proportion of the conductive agent is too high, it will crowd out the pores and active surface, causing an imbalance between compaction and pores, limiting ion transport, and limiting or even decreasing rate and long-cycle performance gains.

[0059] In some embodiments, the thickness of the active layer is 30~100μm.

[0060] Based on the same inventive concept, this application provides a method for preparing a silicon-based negative electrode, comprising the following steps: The active material, binder, and conductive agent are mixed in a solvent to obtain an active slurry. The active slurry is coated onto at least one side of the current collector, and after curing and rolling, a silicon-based negative electrode sheet is obtained. The adhesive includes epoxy resin and amine curing agent; The active materials include carbon-based active materials and silicon-based active materials modified with silane coupling agents.

[0061] It should be understood that all the features and advantages described above regarding the "silicon-based anode sheet" also apply to the "preparation method of the silicon-based anode sheet," and will not be repeated here.

[0062] In some embodiments, the preparation method of the silane coupling agent modified silicon-based active material includes at least one of the following: wet acid catalysis, wet base catalysis, and gas-phase silanization. This application does not specifically limit the preparation method of the silane coupling agent modified silicon-based active material, as long as the silane coupling agent modified silicon-based active material can be prepared.

[0063] In some embodiments, the preparation method of the silane coupling agent modified silicon-based active material is preferably a wet acid catalytic method, including the following steps: Silicon-based active materials are modified by mixing them with a solution containing a silane coupling agent to obtain silane coupling agent-modified silicon-based active materials.

[0064] In some embodiments, the pH value of the modification treatment is 4.5~5.5, and the time is 0.5~3h. As an example, the pH value of the modification treatment can be 4.5, 5, 5.5, etc., or any value within the above range; no specific limitation is made here. As an example, the modification treatment time can be 0.5h, 1.5h, 2.5h, 3h, etc., or any value within the above range; no specific limitation is made here.

[0065] In some embodiments, the curing is carried out under an inert atmosphere, and the curing temperature is 90~120℃, with a time of 20~60 min. As an example, the curing temperature can be 90℃, 100℃, 110℃, 120℃, etc., or any value within the above range; no specific limitation is made here. As an example, the curing time can be 20 min, 40 min, 60 min, etc., or any value within the above range; no specific limitation is made here.

[0066] In some embodiments, the compaction density of the roller press is 1.2~1.7 g / cm³. 3 As an example, the compaction density of roller pressing can be 1.2 g / cm³. 3 1.4g / cm 3 1.6g / cm 3 1.7g / cm 3 "etc." can also be any value within the above range, without being specifically limited here.

[0067] Based on the same inventive concept, this application provides a battery including a negative electrode sheet, wherein the negative electrode sheet is the aforementioned silicon-based negative electrode sheet or a silicon-based negative electrode sheet prepared according to the aforementioned preparation method.

[0068] Because this battery contains the silicon-based negative electrode provided in the embodiments of this application, it has superior structural stability and electrical performance.

[0069] In some embodiments, the battery can be a lithium-ion battery. The battery stacking type is, for example, a wound or stacked battery, and the structural type is, for example, a prismatic (aluminum, steel, etc.) battery, a pouch battery, or a cylindrical battery, etc., without specific limitations. This battery has relatively excellent structural stability and electrical performance.

[0070] In some embodiments, the battery further includes a positive electrode, an electrolyte, and a separator. That is, the battery includes a positive electrode, a silicon-based negative electrode, an electrolyte, and a separator.

[0071] In this embodiment, the materials and structures of the positive electrode current collector, the conductive agent and the binder in the positive electrode active material layer are not limited, and the positive electrode structure and composition known in the art that can be used in secondary batteries can be selected.

[0072] In this embodiment, the specific material or type of the separator is not limited, and any separator known in the art that can be used in secondary batteries can be selected.

[0073] It should also be noted that the battery in this application does not limit the specific material or type of electrolyte. Any components and types known in the art that can be used in secondary batteries can be selected, as long as the purpose of this application can be achieved.

[0074] Since the battery provided in this embodiment of the invention adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0075] The following describes the implementation methods of this application. The implementation methods described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the implementation methods, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents, materials, or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0076] Example 1 Preparation of silicon-based anode sheets The active slurry material was added to the solvent water in a certain proportion and stirred to obtain a slurry. The slurry was coated onto the surface of an 8 μm thick copper foil, and then thermo-cured at 110 °C for 30 min under an inert atmosphere (N2 ≥ 0.9 bar). Subsequently, it was rolled under normal pressure. The above steps were repeated on another layer of copper foil to obtain a silicon-based negative electrode sheet (compacted density 1.55 g·cm³). -3 Thickness 98 μm).

[0077] In the active slurry, the mass ratio of active material (3-(methacryloyloxy)propyltrimethoxysilane modified silicon-carbon composite material: graphite = 20:80), binder (epoxy resin with an epoxy equivalent of 550 g / eq, polyetheramine with an amine hydrogen equivalent of 200 g / eq), conductive agent (vapor-grown carbon fiber: graphene = 13.333 : 6.667), and water is 930:50:20:1000, in g.

[0078] Among them, the silicon-carbon composite material modified with 3-(methacryloyloxy)propyltrimethoxysilane has a loading of about 1% of 3-(methacryloyloxy)propyltrimethoxysilane based on the mass of the silicon-carbon composite material; the ratio of epoxy equivalent to amine hydrogen equivalent is 1; and the mass ratio of epoxy resin to amine curing agent is 36.667:13.333.

[0079] The preparation of 3-(methacryloyloxy)propyltrimethoxysilane (MAPTES) modified silicon-carbon composite material includes: adding a mixed solvent of ethanol and water (volume fraction, ethanol:water = 60:40) to a reactor and adjusting the pH to 5.0; adding MAPTES (1.86 g) dropwise at 25-30 °C and stirring for 10 min for pre-hydrolysis; heating to 50 °C and adding silicon-carbon composite material (186 g) with a particle size Dv50 of 5 μm; stirring at 400 rpm for 60 min; filtering; washing successively with 200 mL of ethanol and 200 mL of deionized water to remove unbonded silane and byproducts; and then drying under nitrogen purging at 60 °C and atmospheric pressure for 8 h to obtain 3-(methacryloyloxy)propyltrimethoxysilane modified silicon-carbon composite material (theoretical loading 1%).

[0080] Example 2 The only difference between Example 2 and Example 1 is that the amount of MAPTES added in Example 2 is halved when preparing the 3-(methacryloyloxy)propyltrimethoxysilane modified silicon-carbon composite material; all other aspects are the same as in Example 1.

[0081] Example 3 The only difference between Example 3 and Example 1 is that the amount of MAPTES added in Example 3 when preparing the 3-(methacryloyloxy)propyltrimethoxysilane modified silicon-carbon composite material is 1.5 times that in Example 1, and all other aspects are the same as in Example 1.

[0082] Example 4 The only difference between Example 4 and Example 1 is that the amount of amine curing agent used in Example 4 is 14.815g, and the final ratio of epoxy equivalent to amine hydrogen equivalent is 0.9. All other aspects are the same as in Example 1.

[0083] Example 5 The only difference between Example 5 and Example 1 is that the amount of amine curing agent used in Example 5 is 12.121g, and the final ratio of epoxy equivalent to amine hydrogen equivalent is 1.1. All other aspects are the same as in Example 1.

[0084] Example 6 The only difference between Example 6 and Example 1 is that the amount of adhesive added in Example 6 is 30g, and all other aspects are the same as in Example 1.

[0085] Example 7 The only difference between Example 7 and Example 1 is that the amount of adhesive added in Example 7 is 70g, and all other aspects are the same as in Example 1.

[0086] Example 8 The only difference between Example 8 and Example 1 is that the amount of conductive agent added in Example 8 is 10g, and the rest is the same as in Example 1.

[0087] Example 9 The only difference between Example 9 and Example 1 is that the amount of conductive agent added in Example 9 is 40g, and all other aspects are the same as in Example 1.

[0088] Example 10 The only difference between Example 10 and Example 1 is that in Example 10, the ratio of 3-(methacryloyloxy)propyltrimethoxysilane-modified silicon-carbon composite material to graphite is 15:85, while the rest are the same as in Example 10.

[0089] Example 11 The only difference between Example 11 and Example 1 is that in the active material of Example 10, the ratio of 3-(methacryloyloxy)propyltrimethoxysilane-modified silicon-carbon composite material to graphite is 25:75, and the rest is the same as in Example 10.

[0090] Comparative Example 1 The only difference between Comparative Example 1-1 and Example 1 is that the amount of MAPTES added in Comparative Example 1-1 when preparing the 3-(methacryloyloxy)propyltrimethoxysilane modified silicon-carbon composite material is 1 / 20 of that in Example 1, and all other aspects are the same as in Example 1.

[0091] The only difference between Comparative Examples 1-2 and Example 1 is that the amount of MAPTES added in Comparative Examples 1-2 when preparing the 3-(methacryloyloxy)propyltrimethoxysilane modified silicon-carbon composite material is 3 times that in Example 1, and all other aspects are the same as in Example 1.

[0092] Comparative Example 2 The only difference between Comparative Example 2-1 and Example 1 is that the amount of amine curing agent used in Comparative Example 2-1 is 22.222g, and the final ratio of epoxy equivalent to amine hydrogen equivalent is 0.6. All other aspects are the same as in Example 1.

[0093] The only difference between Comparative Example 2-2 and Example 1 is that the amount of amine curing agent used in Comparative Example 2-2 is 10.26g, and the final ratio of epoxy equivalent to amine hydrogen equivalent is 1.3. All other aspects are the same as in Example 1.

[0094] Comparative Example 3 The only difference between Comparative Example 3-1 and Example 1 is that the amount of adhesive added in Comparative Example 3-1 is 10g, and all other aspects are the same as in Example 1.

[0095] The only difference between Comparative Example 3-2 and Example 1 is that the amount of adhesive added in Comparative Example 3-2 is 80g, and all other aspects are the same as in Example 1.

[0096] Comparative Example 4 The only difference between Comparative Example 4-1 and Example 1 is that the amount of conductive agent added in Comparative Example 4-1 is 1g, and all other aspects are the same as in Example 1.

[0097] The only difference between Comparative Example 4-2 and Example 1 is that the amount of conductive agent added in Comparative Example 4-2 is 70g, and all other aspects are the same as in Example 1.

[0098] Comparative Example 5 The only difference between Comparative Example 5-1 and Example 1 is that the active material in Comparative Example 5-1 is a silicon-carbon composite material modified with 3-(methacryloyloxy)propyltrimethoxysilane with a graphite ratio of 35:65. All other aspects are the same as in Example 10.

[0099] The only difference between Comparative Example 5-2 and Example 1 is that in Comparative Example 5-2, the ratio of 3-(methacryloyloxy)propyltrimethoxysilane-modified silicon-carbon composite material to graphite is 5:95; otherwise, they are the same as in Example 10.

[0100] Performance testing 1. Silicon-based negative electrode peel force test First, the silicon-based negative electrode sheet, which has been washed with dimethyl carbonate and vacuum dried, is cut into strips of standard size (2.0cm × 10.0cm). Next, use double-sided tape to fix the strip sample onto a flat, thin steel plate, ensuring that the tape is stuck in the center of the steel plate. Then, peel off the protective layer of the double-sided tape, stick the strip sample of the electrode to be tested onto the double-sided tape, and use a pressure roller to evenly roll the strip sample to ensure good adhesion. Next, tear off the unattached end, bend the exposed end of the electrode upwards, and clamp it in the upper fixture of the tensile testing machine for a 180° peel test. Record the tensile force curve. Select the section where the tensile force changes by no more than 10% as the stable peeling section. Finally, divide the average tensile force of this section by the width of the long sample electrode to calculate the peel strength of the negative electrode.

[0101] 2. Electrical performance testing (1) Battery preparation Preparation of the positive electrode: The positive electrode active material LiNi... 0.8 Co 0.1 Mn 0.1 O2, conductive carbon black (SP), carbon nanotubes, and polyvinylidene fluoride (PVDF5130) binder are mixed in a mass ratio of 96:1:1:2. Then, N-methylpyrrolidone (NMP) is added, and the mixture is stirred and mixed uniformly to form a stable positive electrode slurry with a solid content of 75%. The positive electrode slurry is uniformly coated on a 12μm aluminum foil for the positive electrode current collector, and then dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0102] The diaphragm has a base film of polyethylene (PE) with a thickness of 9 μm and ceramic coatings on both sides of the base film with a thickness of 1.0 μm each.

[0103] Electrolyte: In a glove box filled with inert gas, lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), ethylene sulfate (DTD), and vinylene carbonate (VC) are mixed in a mass percentage ratio of 10.0: 22.0: 53.0: 3.0: 7.0: 5.0 to obtain the electrolyte.

[0104] Battery assembly: The positive electrode sheet and silicon-based negative electrode sheet are rolled and slit respectively, and then wound together with the separator according to the set process to form a 21700 cylindrical battery core. Subsequently, the battery core is fixed to the pre-made connecting piece by welding and then installed into a metal battery casing. After completing key processes such as electrolyte injection, sealing, and formation, a lithium-ion battery is obtained. This lithium-ion battery uses a cylindrical casing with an external dimension of 21.0 mm in diameter and 70.0 mm in length, conforming to the 21700 standard specifications.

[0105] (2) Capacity retention test after 200 cycles The battery was placed in a 45°C constant temperature chamber for 6 hours and tested according to the following steps: it was charged at a constant current of 0.1C to 4.25V, then switched to constant voltage charging until the current dropped to 0.01C, and left to stand for 30 minutes; it was then discharged at a constant current of 0.1C to 2.5V. Charge at a constant current rate of 1C to 4.25V, then switch to constant voltage charging until the current drops to 0.1C, and let stand for 30 minutes; discharge at a constant current rate of 1C to 2.5V (the capacity at this step is recorded as the discharge capacity), and let stand for 30 minutes; repeat this step 200 times, and record the ratio of the discharge capacity of the 200th cycle to the discharge capacity of the first cycle as the capacity retention rate (Note: the higher the capacity retention rate, the longer the service life of the electrode).

[0106] (3) Expansion rate test of silicon-based negative electrode after 200 cycles The thickness of the fresh negative electrode sheet after rolling was measured using a laser thickness gauge and recorded as H1. The battery electrode sheet after the 200-cycle capacity retention test was disassembled, washed with dimethyl carbonate to remove electrolyte, and vacuum dried; the thickness was then measured and recorded as H2. Electrode expansion rate = (H2 - H1) / H1 * 100%.

[0107] The test results of each embodiment and comparative example are shown in Table 1.

[0108] Table 1 The test results from Examples 1-3 and Comparative Example 1 show that the loading of the silane coupling agent determines the density of covalent anchoring points and interfacial energy on the surface of the silicon-based active material. By providing reactive end groups, it chemically reacts with the epoxy-amine curing network to form effective connection points in the interfacial layer, improving interfacial shear strength and dimensional stability. This process does not change the crosslinking density of the bulk binder phase, which is controlled by the epoxy / amine equivalent ratio and the curing process. If the loading of the silane coupling agent is too low, the silicon-based active material mainly relies on physical adsorption and mechanical intercalation, resulting in reduced interfacial shear strength. During cyclic expansion and contraction, microcracks, pulverization, and localized debonding are more likely to occur, leading to poor current distribution and inducing repeated SEI rupture. Peel strength and capacity decrease synchronously, and the expansion inhibition ability is significantly weakened. If the loading of the silane coupling agent is too high, the degree of interfacial densification is improved, which is beneficial for suppressing particle displacement of the silicon-based active material. However, excessively high interfacial densification increases the resistance to cross-interfacial electron and ion migration, ultimately adversely affecting the battery's rate capability and long-term cycling performance.

[0109] The test results from Examples 1, 4-5, and Comparative Example 2 show that the ratio of the epoxy equivalent of the epoxy resin to the amine hydrogen equivalent of the amine curing agent in the binder directly determines the effective crosslinking density of the binder phase. If the ratio is too low, there is an excess of active hydrogen, and unreacted epoxy groups coexist with loose chain segments. During battery cycling, the coating undergoes viscoelastic creep and stress relaxation, resulting in significantly poorer interfacial adhesion and structural stability, and an increased expansion rate. If the ratio is too high, there is a relative excess of epoxy groups, making the three-dimensional network structure of the binder phase harder and more brittle. Local etherified or unconverted epoxy group residues appear, reducing the crack propagation threshold and leading to a decrease in the long cycle life of the silicon-based anode sheet.

[0110] The test results from Examples 1, 6-7, and Comparative Example 3 show that if the binder content is too low, the pore walls are not completely coated, the particles mainly make point contact, the load transfer is uneven, the local current density increases and side reactions are triggered, the SEI is prone to repeated breakage, manifested as a significant decrease in peel strength and accelerated cycle decay. If the binder content is too high, although adhesion and swelling suppression are slightly improved, the reduced pore connectivity increases ion diffusion paths, the intra-sheet polarization increases, and the capacity remains low.

[0111] The test results from Examples 1, 8-9, and Comparative Example 4 show that if the proportion of conductive agent is too low, the conductive network in the active layer does not reach the percolation threshold, resulting in a significant increase in sheet resistance, increased battery polarization, increased local overpotential, more pronounced side reactions and SEI thickening, and a significant decrease in cycle retention. If the proportion of conductive agent is too high, it will crowd out the pores and active surface, causing an imbalance between compaction and pores, limiting ion transport, and limiting or even decreasing rate and long-cycle gains.

[0112] The test results from Examples 1, 10-11, and Comparative Example 5 show that the mass ratio of silane coupling agent-modified silicon-based active material directly affects the specific capacity and volume expansion of the battery. Limiting the mass ratio of carbon-based active material to silane coupling agent-modified silicon-based active material within a suitable range, combined with the silane coupling agent-modified silicon-based active material and the metering curing scheme of this application, can result in higher energy density and longer cycle life for the battery. If the ratio is too low, the proportion of silane coupling agent-modified silicon-based active material will be too large. Although this can improve the reversible capacity of the battery, the large volume change of silicon during lithium insertion and extraction makes it difficult for the silane coupling agent-modified silicon-based active material to be completely anchored on the three-dimensional network of the binder phase. Simultaneously, the buffering capacity of the three-dimensional network of the binder phase is insufficient to cope with the volume expansion of silicon. During cycling, fresh exposed surfaces are easily generated, repeatedly forming and damaging the SEI, leading to increased expansion rate and decreased capacity. If the ratio of the two is too large, the proportion of silicon-based active material modified by silane coupling agent will be too small. This can significantly reduce volumetric stress and the probability of interface damage, and make it easier to meet adhesion and dimensional stability requirements, but it will lead to a low specific capacity of the battery.

[0113] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0114] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0115] It should be noted that the terms "and / or" or " / " used herein are merely descriptions of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The singular forms "a," "described," and "the" used in the embodiments of the invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0116] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silicon-based negative electrode, characterized in that, The silicon-based anode sheet includes: current collector; An active layer is disposed on at least one side surface of the current collector along the thickness direction, and the active layer includes an active material, a binder phase, and a conductive agent; The active materials include carbon-based active materials and silicon-based active materials modified with silane coupling agents; The binder phase comprises a three-dimensional network structure composed of epoxy-amine.

2. The silicon-based negative electrode according to claim 1, characterized in that, The binder phase is prepared from epoxy resin and amine curing agent; The epoxy equivalent in the epoxy resin is 450~900 g / eq; the amine hydrogen equivalent in the amine curing agent is 90~350 g / eq; when preparing the binder phase, the ratio of the epoxy equivalent in the epoxy resin to the amine hydrogen equivalent in the amine curing agent is controlled to be 0.8~1.

1.

3. The silicon-based negative electrode according to claim 1, characterized in that, The active material satisfies at least one of the following characteristics (1) to (3): (1) In the silane coupling agent modified silicon-based active material, the silane coupling agent is loaded on at least part of the surface of the silicon-based active material; Preferably, the silane coupling agent loading is defined as the percentage of the silane coupling agent by mass of the silicon-based active material, and the silane coupling agent loading is 0.3% to 2%. Preferably, the silane coupling agent comprises at least one of 3-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and isocyanate propyltriethoxysilane; Preferably, the silicon-based active material includes at least one of silicon-carbon composite material, elemental silicon, silicon oxide, and porous silicon; Preferably, the average particle size Dv50 of the silicon-based active material is 0.1~10 μm; (2) The mass ratio of the carbon-based active material to the silane coupling agent modified silicon-based active material is (70~90):(10~30); (3) The carbon-based active material includes at least one of graphite, soft carbon, hard carbon, and mesophase carbon microspheres.

4. The silicon-based negative electrode according to claim 1, characterized in that, The conductive agent includes at least one of vapor-grown carbon fiber and graphene; Preferably, the conductive agent is selected from a mixture of vapor-grown carbon fiber and graphene, wherein the mass ratio of vapor-grown carbon fiber to graphene is 1:(0.2~1).

5. The silicon-based negative electrode according to claim 1, characterized in that, The mass ratio of the active material, binder phase, and conductive agent is 100:(2~8):(0.5~6).

6. The method for preparing a silicon-based negative electrode sheet according to any one of claims 1 to 5, characterized in that, Includes the following steps: The active material, binder, and conductive agent are mixed in a solvent to obtain an active slurry. The active slurry is coated onto at least one side of the current collector, and after curing and rolling, a silicon-based negative electrode sheet is obtained. The adhesive includes epoxy resin and amine curing agent; The active materials include carbon-based active materials and silicon-based active materials modified with silane coupling agents.

7. The preparation method according to claim 6, characterized in that, The preparation method of the silane coupling agent modified silicon-based active material includes at least one of the following: wet acid catalysis, wet alkaline catalysis, and gas-phase silanization. The preferred method for preparing the silane coupling agent-modified silicon-based active material is a wet acid catalysis method, comprising the following steps: Silicon-based active materials are modified by mixing them with a solution containing a silane coupling agent to obtain silane coupling agent-modified silicon-based active materials. The pH value of the modification treatment is 4.5~5.5, and the time is 0.5~3h.

8. The preparation method according to claim 6, characterized in that, The curing is carried out under an inert atmosphere at a temperature of 90-120°C for 20-60 minutes.

9. The preparation method according to claim 6, characterized in that, The compaction density of the roller press is 1.2~1.7 g / cm³. 3 .

10. A battery, comprising a negative electrode, characterized in that, The negative electrode is the silicon-based negative electrode according to any one of claims 1 to 5, or includes the silicon-based negative electrode prepared by the preparation method according to any one of claims 6 to 9.

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