Silicon oxide-based skeleton supported bismuth material, preparation method and application thereof and lithium ion battery

Abstract

The application provides a silicon oxide-based framework loaded bismuth material, a preparation method and application thereof and a lithium ion battery, and relates to the technical field of lithium ion battery negative materials. a O b @C, is a porous material with a hollow three-dimensional through framework, the framework adopts a silicon-based oxide, the hollow inside is caused by heat reduction of bismuth oxide, bismuth metal is distributed on the pore wall by diffusion along the pore channel, and finally a carbon coating is performed. Compared with a traditional porous carbon framework bismuth-based porous material, the porous framework designed in the application has a hollow three-dimensional through structure derived from a precursor, can autonomously control the hollow number of the framework, improves the diffusion rate, and also makes the diffusion direction of lithium ions have selectivity. The silicon-based oxide serving as the framework can make the overall material have sufficient rigidity, and can better inhibit the volume expansion of bismuth in the alloying process.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery anode material technology, and in particular to a silicon oxide-based framework supported bismuth material, its preparation method and application, and lithium-ion batteries. Background Technology

[0002] As the core of modern energy storage, the performance improvement of lithium-ion batteries is facing severe limitations due to the availability of anode materials. Currently, commercial lithium-ion batteries generally use graphite as the anode material, which operates through the lithium-ion insertion / extraction mechanism, with a theoretical specific capacity of only 372 mAh / g. Although graphite has advantages such as low cost and long cycle life, its inherent limitations cannot meet the growing demands for high energy density and fast charging in fields such as electric vehicles and large-scale energy storage.

[0003] To overcome the limitations of graphite materials, the scientific community has turned its attention to alloy-type anode materials, among which bismuth (Bi) has shown great potential due to its unique advantages. Bismuth forms a Li3Bi alloy with lithium, achieving a theoretical capacity of up to 385 mAh / g, and possesses a superior lithium-ion diffusion coefficient compared to graphite, as well as a suitable operating potential (approximately 0.8 V vs. Li). + Bismuth (Li) theoretically allows it to simultaneously improve battery energy density, power density, and safety. However, the commercial application of bismuth anodes is limited by a core bottleneck: during alloying / dealloying, bismuth undergoes a huge volume change (>200%), which leads to the pulverization of active material particles and their detachment from the current collector; repeated rupture and regeneration of the solid electrolyte interphase (SEI) film continuously consumes electrolyte and active lithium, resulting in rapid capacity decay and overall electrode structure damage, and a sharp decline in cycle life.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One objective of this invention is to provide a bismuth-loaded material with a silicon oxide-based framework, thereby addressing at least one of the technical problems existing in the prior art. The bismuth-loaded material with a silicon oxide-based framework possesses strong mechanical confinement and territorial effects, stable interfacial properties, and optimized conductive networks and ion transport pathways. This invention utilizes a template method combined with a thermal reduction process to construct a composite material with a rigid framework of silicon oxide-based material, featuring a hollow, three-dimensionally interconnected pore structure. Metallic bismuth is uniformly distributed within the pore walls, providing sufficient volume expansion space for bismuth during charge and discharge. Simultaneously, the mechanical strength of the framework inhibits material pulverization, improving cycle stability.

[0006] The second objective of this invention is to provide an application of a silicon oxide-based framework-supported bismuth material in the preparation of lithium-ion battery anodes.

[0007] The third objective of this invention is to provide a lithium-ion battery.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0009] In a first aspect, the present invention provides a bismuth-supported material on a silicon oxide-based framework, the material having a porous structure formed by internal hollow regions, the porous structure being a three-dimensional interconnected nanopore network; wherein bismuth is disposed on the inner wall surface of the three-dimensional interconnected pores.

[0010] The method for preparing the silicon oxide-based framework-supported bismuth material includes the following steps: constructing a micelle template with a surfactant and introducing silicate and bismuth source, obtaining a precursor through crystallization and calcination, then precipitating bismuth through thermal reduction to form a three-dimensional through-hole structure, and finally performing carbon coating to obtain the silicon oxide-based framework-supported bismuth material.

[0011] In some preferred embodiments, the number of hollow cells is N, where N≥1;

[0012] Preferably, the hollow dimension of the bismuth-supported bismuth material on the silicon oxide framework is half of the average of the maximum and minimum lengths passing through the midpoint in the two-dimensional plane, R1, where 25 nm ≤ R1 ≤ 500 nm.

[0013] Preferably, the bismuth-supported bismuth material on the silicon oxide framework is in bulk form.

[0014] In some preferred embodiments, the general structural formula of the bismuth material supported on the silicon oxide framework is Bi / SiM. a O b @C;

[0015] Preferably, SiM a O b A silicon-based oxide framework is used to support bismuth metal, M includes one or more of Al, Ti, and Mg, 0≤a≤2, 0<b≤3;

[0016] Preferably, Bi metal nanoparticles are deposited on the pore walls, wherein half of the average of the maximum and minimum lengths of the primary particles passing through the midpoint in the two-dimensional plane is R2, 1 nm ≤ R2 ≤ 50 nm, and the deposition thickness is L1, 1 nm ≤ L1 ≤ 50 nm; C is a carbon coating layer with a thickness of L2, 1 nm ≤ L2 ≤ 10 nm.

[0017] In some preferred embodiments, the Bi metal is obtained by thermal reduction of bismuth oxide, and half of the average of the maximum and minimum lengths of bismuth oxide passing through the midpoint in the two-dimensional plane is R3, and 25 nm ≤ R3 ≤ 500 nm.

[0018] In some preferred embodiments, the mass fraction of bismuth in the silicon oxide-based framework-supported bismuth material is W1, where W1 is based on the total mass of the material and 50 wt% ≤ W1 < 100 wt%.

[0019] Preferably, the bismuth-supported material on the silicon oxide framework contains SiM a O b The mass fraction is W2, where W2 is based on the total mass of the material and W2 ≤ 50 wt%.

[0020] Preferably, the mass fraction of the carbon layer in the silicon oxide-based framework-supported bismuth material is W3, where W3 is based on the total mass of the material and is ≤15wt%.

[0021] In some preferred embodiments, the specific surface area of ​​the bismuth-supported bismuth material on the silicon oxide framework is 0.1-10 m². 2 / g;

[0022] Preferably, the particle size D50 of the bismuth material supported on the silicon oxide framework is 0.1-10 μm;

[0023] Preferably, the helium true density of the bismuth-supported bismuth material on the silicon oxide framework is 1-5 g / cm³. 3 .

[0024] In some preferred embodiments, the method for preparing the silicon oxide-based framework-supported bismuth material includes the following steps:

[0025] Step S1: Mix the surfactant with water and stir to form a micelle solution. Then add a silicate solution, adjust the pH with dilute acid, and stir to obtain a template agent solution.

[0026] Step S2: Add bismuth source to the template agent preparation solution, stir, and then place it in a reaction vessel to crystallize and obtain seed crystals;

[0027] Step S3: After calcining the seed crystal in air, a bismuth-based precursor is obtained;

[0028] Step S4: The bismuth-based precursor is subjected to reduction heat treatment and vacuum heat treatment in sequence to obtain a semi-finished product;

[0029] Step S5: Place the semi-finished product in a carbon source atmosphere for carbon coating to obtain a silicon oxide-based framework supported bismuth material.

[0030] Preferably, in step S1, the stirring temperature is 30-60℃ and the pH is 9.5-11.5;

[0031] Preferably, the surfactant comprises hexadecyltrimethylammonium bromide;

[0032] Preferably, the silicate comprises sodium metasilicate;

[0033] Preferably, the dilute acid includes sulfuric acid;

[0034] Preferably, in step S2, the reaction temperature of the reactor is 80-120℃;

[0035] Preferably, the bismuth source in step S2 includes at least one of bismuth trioxide and bismuth citrate;

[0036] Preferably, in step S3, the calcination temperature is 400-600℃;

[0037] Preferably, in step S4, the temperatures of the reduction heat treatment and the vacuum heat treatment are 500-1000℃;

[0038] Preferably, in step S4, the reducing atmosphere of the reduction heat treatment includes carbon monoxide;

[0039] Preferably, in step S5, the carbon coating temperature is 400-1000℃;

[0040] Preferably, in step S5, the carbon source atmosphere includes one or more combinations of acetylene, ethylene, and propylene.

[0041] Thirdly, the present invention provides an application of a silicon oxide-based framework supported bismuth material or a silicon oxide-based framework supported bismuth material prepared by the aforementioned preparation method in the preparation of a lithium-ion battery anode.

[0042] Fourthly, the present invention provides a lithium-ion battery, wherein the negative electrode of the lithium-ion battery uses an active material comprising the aforementioned silicon oxide-based framework-supported bismuth material or a silicon oxide-based framework-supported bismuth material prepared by the aforementioned preparation method.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The bismuth-loaded bismuth material supported by the silicon oxide-based framework provided by this invention, by constructing a three-dimensional interconnected nanoporous network and uniformly distributing bismuth on the inner wall of the pores, can provide sufficient volume expansion space for bismuth during charging and discharging, effectively alleviating stress accumulation caused by alloying reaction and inhibiting material pulverization and structural collapse; at the same time, the rigid silicon oxide-based framework plays a confined support role, maintaining the structural integrity of the electrode material, while the interconnected pores facilitate the rapid transport of lithium ions and electrons, significantly improving the rate performance and cycle stability of the material. Attached Figure Description

[0045] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of the silicon oxide-based framework-supported bismuth material provided by the present invention;

[0047] Figure 2 SEM image of the bismuth-supported bismuth material on a silicon oxide framework prepared in Example 1;

[0048] Figure 3 SEM image of the bismuth-supported silica-based framework material prepared in Example 2;

[0049] Figure 4 SEM image of the bismuth-supported silica-based framework material prepared in Example 3;

[0050] Figure 5 SEM image of the bismuth-supported bismuth material on a silicon oxide framework prepared in Example 4;

[0051] Figure 6 SEM image of the bismuth-supported silica-based framework material prepared in Example 5;

[0052] Figure 7 SEM image of the bismuth-supported silica-based framework material prepared in Example 6;

[0053] Figure 8 SEM image of the bismuth-supported bismuth material on a silicon oxide framework prepared in Example 7;

[0054] Figure 9 SEM image of the bismuth-supported silica-based framework material prepared in Example 8;

[0055] Figure 10 The image shows a SEM image of the carbon framework-supported bismuth material prepared in Comparative Example 1.

[0056] Figure 11 The image shows a SEM image of the carbon framework-supported bismuth material prepared in Comparative Example 2.

[0057] Figure 12 Here is a SEM image of the silicon oxide-supported bismuth material prepared in Comparative Example 3;

[0058] Figure 13 The image shows the XRD pattern of the bismuth-supported silicon oxide framework material prepared in Example 1. Detailed Implementation

[0059] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0060] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] like Figure 1 As shown, the first aspect of the present invention provides a silicon oxide-based framework-supported bismuth material, the material having a porous structure formed by internal hollow regions, the porous structure being a three-dimensional interconnected nanopore network; wherein bismuth is disposed on the inner wall surface of the three-dimensional interconnected pores.

[0062] To address the issue of the large volume effect in bismuth anodes, this invention proposes a composite anode material with a porous silicon oxide framework. This material utilizes a template method combined with thermal reduction to construct three-dimensional nanopores and uniformly deposit bismuth within the framework. Compared to traditional graphite or simple carbon-based composite anodes, the silicon oxide-bismuth composite structure designed in this invention achieves multiple synergistic effects. For instance, the silicon oxide framework exhibits strong mechanical confinement and localization effects, strictly limiting the volume expansion / contraction of bismuth within the pores, fundamentally suppressing the pulverization of the electrode material and maintaining structural integrity. Furthermore, the hollow, three-dimensional interconnected structure left by the thermal reduction of bismuth oxide provides sufficient expansion space for bismuth and also provides an ideal channel for the rapid transport of electrons and ions. The uniformly distributed nano-bismuth further shortens the ion diffusion distance, collectively endowing this composite material with excellent rate performance.

[0063] This invention solves a core technical challenge that has limited the application of bismuth anodes by innovatively combining high-capacity bismuth with a stable and precisely controllable silicon oxide-based framework. The resulting composite anode material not only has a theoretical capacity far exceeding that of graphite, but also achieves breakthrough improvements in cycle life and fast-charging performance.

[0064] Specifically, bismuth-supported materials with a silicon oxide framework possess a hollow, three-dimensional interconnected structure. This structure provides bismuth with sufficient expansion space and ion / electron diffusion capabilities. Furthermore, the combination of the template method and the thermal reduction method allows for the autonomous design of the number and size of hollow structures. The general structural formula for bismuth-supported materials with a silicon oxide framework is: Bi / SiM a O b @C is a porous material with a hollow, three-dimensionally interconnected framework. The framework is made of silicon-based oxide, and its hollow structure is achieved through the thermal reduction of bismuth oxide. Bismuth metal diffuses and deposits along the pore walls, and is finally coated with a layer of carbon. Compared to traditional porous carbon-based bismuth-based porous materials, the porous framework designed in this invention has a hollow, three-dimensionally interconnected structure derived from the precursor. It can autonomously control the number of hollow pores in the framework, which not only improves the diffusion rate but also makes the diffusion direction of lithium ions selective. Using silicon-based oxide as the framework provides sufficient rigidity to the overall material, better suppressing the volume expansion of bismuth during the alloying process.

[0065] The silicon oxide-based framework-supported bismuth material provided by this invention, through the thermal reduction of bismuth oxide, constructs a porous material with a hollow, three-dimensional, interconnected framework, which has the following advantages:

[0066] 1. Compared to carbon frameworks, silicon-based oxide frameworks exhibit strong mechanical confinement and localization effects, which fundamentally suppress the pulverization of electrode materials and maintain the integrity of the structure.

[0067] 2. The hollow, three-dimensional interconnected structure left by the thermal reduction of bismuth oxide provides sufficient expansion space for bismuth, providing an ideal channel for the rapid transport of electrons and ions, thus endowing the composite material with excellent rate performance.

[0068] 3. Bismuth, as a metal, is also an excellent conductor. It forms a conductive network, which makes up for the poor conductivity of silicon oxide and silicon. The uniformly distributed nano-bismuth has higher electrochemical activity and lower internal resistance, which gives the composite material excellent cycle stability.

[0069] In some preferred embodiments, the number of hollow cells is N, where N≥1;

[0070] Preferably, the hollow dimension of the bismuth-supported silicon oxide framework material is R1, which is half the average of the maximum and minimum lengths passing through the midpoint in the two-dimensional plane, and 25 nm ≤ R1 ≤ 500 nm. For example, it can be 25 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, etc.

[0071] Preferably, the bismuth-supported bismuth material on the silicon oxide framework is in bulk form.

[0072] In some preferred embodiments, the general structural formula of the bismuth material supported on the silicon oxide framework is Bi / SiM. a O b @C;

[0073] Preferably, the silicon oxide-based framework in the bismuth-supported silicon oxide framework can be a silicon oxide-based framework doped with silicon oxide or other elements, with the general structural formula SiM. a O b M includes one or more of Al, Ti, Mn, Na, K, Mg, Li, Ca and C, while 0≤a≤2 and 0<b≤3, which gives the skeleton more specificity;

[0074] Preferably, Bi is bismuth metal, and Bi metal nanoparticles are deposited on the pore walls. R2 is half the average of the maximum and minimum lengths of the primary particles passing through the midpoint in the two-dimensional plane, where 1 nm ≤ R2 ≤ 50 nm. For example, it can be 1 nm, 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc. The deposition thickness is L1, where 1 nm ≤ L1 ≤ 50 nm. For example, it can be 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc. The nanoscale gives bismuth metal higher electrochemical activity. In addition, in order to suppress corrosion caused by direct contact between acidic substances in the electrolyte and bismuth metal, a carbon coating layer is required. C is the carbon coating layer with a thickness of L2, where 1 nm ≤ L2 ≤ 10 nm. For example, it can be 1 nm, 5 nm, 10 nm, etc.

[0075] In some preferred embodiments, the Bi metal is obtained by thermal reduction of bismuth oxide, and half of the average of the maximum and minimum lengths of bismuth oxide passing through the midpoint in the two-dimensional plane is R3, and 25 nm≤R3≤500 nm, for example, it can be 25 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, etc.

[0076] In some preferred embodiments, the mass fraction of bismuth in the silicon oxide-based framework-supported bismuth material is W1, where W1 is based on the total mass of the material and is 50 wt% ≤ W1 < 100 wt%, for example, it can be 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt%, etc.

[0077] Preferably, the bismuth-supported material on the silicon oxide framework contains SiM a O bThe mass fraction is W2, which is based on the total mass of the material. W2 ≤ 50 wt%, for example, it can be 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, etc., and more preferably W2 ≤ 45 wt%.

[0078] Preferably, the mass fraction of the carbon layer in the bismuth-supported bismuth material on the silicon oxide framework is W3, where W3 is based on the total mass of the material and is ≤15wt%. For example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, etc.

[0079] In some preferred embodiments, the specific surface area of ​​the bismuth-supported bismuth material on the silicon oxide framework is 0.1-10 m². 2 / g;

[0080] Preferably, the particle size D50 of the bismuth material supported on the silicon oxide framework is 0.1-10 μm;

[0081] Preferably, the helium true density of the bismuth-supported bismuth material on the silicon oxide framework is 1-5 g / cm³. 3 .

[0082] The method for preparing the silicon oxide-based framework-loaded bismuth material includes: constructing a micelle template with a surfactant and introducing silicate and bismuth source, obtaining a precursor through crystallization and calcination, then precipitating bismuth through thermal reduction to form a three-dimensional through-hole structure, and finally performing carbon coating to obtain the silicon oxide-based framework-loaded bismuth material.

[0083] In some preferred embodiments, the preparation method includes the following steps:

[0084] Step S1: Prepare template agent solution. Mix surfactant with water and stir at low temperature to form micelle solution. Then add silicate solution, adjust pH with dilute acid, and stir to obtain template agent solution.

[0085] Step S2: Add bismuth source. Add bismuth source to the template agent preparation solution, stir evenly, and then place it in a reaction vessel to crystallize and obtain seed crystals.

[0086] Step S3: Filter and wash, then calcine the seed crystal in air to obtain the bismuth-based precursor;

[0087] Step S4: Thermal reduction. The bismuth-based precursor is heat-treated under a reducing atmosphere, followed by vacuum heat treatment to obtain a semi-finished product.

[0088] Step S5: Carbon coating. The semi-finished product is placed in a carbon source atmosphere for carbon coating to finally obtain a silicon oxide-based framework supported bismuth material;

[0089] Preferably, in step S1, the low-temperature stirring temperature is 30-60℃, for example, it can be 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, etc., and the pH is 9.5-11.5;

[0090] Preferably, the surfactant comprises one or more combinations of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, sodium dodecyl sulfate, dimethylimidazole, sodium carboxymethyl cellulose, sodium alkylbenzene sulfonate, fatty alcohol polyoxyethylene ether phosphate and nonylphenol polyoxyethylene ether phosphate.

[0091] Preferably, the silicate comprises one or more combinations of sodium metasilicate, potassium silicate, lithium silicate, ethyl silicate, calcium metasilicate, tetramethylammonium hydroxide silicate, silica sol, hydrated sodium metasilicate, ethyl orthosilicate, and magnesium silicate.

[0092] Preferably, the dilute acid includes one or more combinations of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, carbonic acid, and acetic acid;

[0093] Preferably, in step S2, the reaction temperature of the reactor is 80-120℃, for example, it can be 80℃, 90℃, 100℃, 110℃, 120℃, etc.

[0094] Preferably, the bismuth source in step S2 includes one or more combinations of bismuth trioxide, bismuth pentoxide, bismuth citrate, bismuth tartrate, bismuth acetylacetonate, bismuth ammonium nitrate, and bismuth acetate.

[0095] Preferably, in step S3, the calcination temperature is 400-600℃, for example, it can be 400℃, 500℃, 600℃, etc.

[0096] Preferably, in step S4, the temperature of the reduction heat treatment and the vacuum heat treatment is 500-1000℃, for example, it can be 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, etc.

[0097] Preferably, the reducing atmosphere in step S4 includes one or more combinations of carbon monoxide, methane, and hydrogen.

[0098] Preferably, in step S5, the carbon coating temperature is 400-1000℃, for example, it can be 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, etc.

[0099] Preferably, in step S5, the carbon source atmosphere includes one or more combinations of acetylene, ethylene, and propylene.

[0100] The second aspect of this invention provides the application of a silicon oxide-based framework-supported bismuth material in the preparation of a lithium-ion battery anode.

[0101] A third aspect of the present invention provides a lithium-ion battery, wherein the negative electrode of the lithium-ion battery uses an active material comprising the aforementioned silicon oxide-based framework-supported bismuth material.

[0102] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0103] Used in the examples and comparative examples:

[0104] The CAS number for bismuth oxide (bismuth trioxide) is 1304-76-3;

[0105] The CAS number for bismuth citrate is 813-93-4.

[0106] Example 1

[0107] This embodiment provides a silicon oxide-based framework-supported bismuth material, wherein the Bi metal content is 80% by mass, the SiO2 content is 18% by mass, and the carbon layer content is 2%. The preparation method is as follows:

[0108] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template solution.

[0109] Next, 21g of bismuth citrate was added, and after stirring for half an hour, it was transferred to a reaction vessel and reacted at 100°C for 24 hours to obtain seed crystals.

[0110] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0111] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0112] Finally, the silicon oxide-supported bismuth material was obtained by heat treatment at 650°C for 2 hours under an acetylene atmosphere.

[0113] Physicochemical tests revealed that the material has a particle size of 8.1 μm and a specific surface area of ​​0.83 m². 2 / g, the true density of helium is 1.84g / cm³. 3 .

[0114] Example 2

[0115] This embodiment provides a silicon oxide-based framework-supported bismuth material, wherein the Bi metal content is 74% by mass, the SiO2 content is 23% by mass, and the carbon layer content is 3%. The preparation method is as follows:

[0116] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11.2 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template agent solution.

[0117] Next, add 15g of bismuth citrate, stir for half an hour, transfer to a reaction vessel, and react at 100℃ for 24 hours to obtain seed crystals;

[0118] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0119] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 700°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0120] Finally, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a silicon oxide-supported bismuth material.

[0121] Physicochemical tests revealed that the material has a particle size of 8.3 μm and a specific surface area of ​​0.92 m². 2 / g, the true density of helium is 1.63g / cm³. 3 .

[0122] Example 3

[0123] This embodiment provides a silicon oxide-based framework-supported bismuth material, wherein the Bi metal content is 68% by mass, the SiO2 content is 28% by mass, and the carbon layer content is 4%. The preparation method is as follows:

[0124] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11.5 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template solution.

[0125] Next, add 7g of BiO2, stir for half an hour, transfer to a reaction vessel, and react at 100℃ for 24 hours to obtain seed crystals;

[0126] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0127] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0128] Finally, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a silicon oxide-supported bismuth material.

[0129] Physicochemical tests revealed that the material has a particle size of 8.4 μm and a specific surface area of ​​0.98 m². 2 / g, the true density of helium is 1.43g / cm³. 3 .

[0130] Example 4

[0131] This embodiment provides a silicon oxide-based framework supported bismuth material, wherein the Bi metal content is 80% by mass, and SiAl... 0.1 O 2.15 The mass content is 18%, and the carbon layer content is 2%. The preparation method is as follows:

[0132] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 3.83 g of sodium metasilicate and 1.17 g of aluminum nitrate nonahydrate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template agent solution.

[0133] Next, add 10g of Bi2O3, stir for half an hour, transfer to a reaction vessel, and react at 100℃ for 24 hours to obtain seed crystals;

[0134] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0135] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0136] Finally, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a silicon oxide-supported bismuth material.

[0137] Physicochemical tests revealed that the material has a particle size of 9.2 μm and a specific surface area of ​​0.78 m². 2 / g, the true density of helium is 2.11g / cm³. 3 .

[0138] Example 5

[0139] This embodiment provides a silicon oxide-based framework supported bismuth material, wherein the Bi metal content is 74% by mass, and SiTi 0.1 O 2.2 The mass content is 23%, and the carbon layer content is 3%. The preparation method is as follows:

[0140] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add an appropriate amount of 3.91 g of sodium metasilicate and 1.09 g of tetrabutyl titanate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template agent solution.

[0141] Next, 13.4g of bismuth citrate was added according to the set ratio, and after stirring for half an hour, it was transferred to a reaction vessel and reacted at 100°C for 24 hours to obtain seed crystals;

[0142] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0143] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0144] Finally, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a silicon oxide-supported bismuth material.

[0145] Physicochemical tests revealed that the material has a particle size of 8.3 μm and a specific surface area of ​​0.84 m². 2 / g, the true density of helium is 1.76g / cm³. 3 .

[0146] Example 6

[0147] This embodiment provides a silicon oxide-based framework supported bismuth material, wherein the Bi metal content is 68% by mass, and SiMg... 0.2 O 2.2 The mass content is 28%, and the carbon layer content is 4%. The preparation method is as follows:

[0148] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 3.6 g of sodium metasilicate and 1.4 g of magnesium sulfate heptahydrate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template agent solution.

[0149] Next, 9.2g of bismuth citrate was added, and after stirring for half an hour, it was transferred to a reaction vessel and reacted at 100°C for 24 hours to obtain seed crystals;

[0150] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0151] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0152] Finally, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a silicon oxide-supported bismuth material.

[0153] Physicochemical tests revealed that the material has a particle size of 9.7 μm and a specific surface area of ​​0.71 m². 2 / g, the true density of helium is 1.39g / cm³. 3 .

[0154] Example 7

[0155] This embodiment provides a bismuth-supported material with a silicon oxide-based framework, which differs from Embodiment 1 in that: the Bi metal mass content is 50%, the SiO2 mass content is 35%, and the carbon layer content is 15%. The preparation method is as follows:

[0156] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template solution.

[0157] Next, 6.7g of bismuth citrate was added, and after stirring for half an hour, it was transferred to a reaction vessel and reacted at 100°C for 24 hours to obtain seed crystals.

[0158] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0159] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0160] Finally, the silicon oxide-supported bismuth material was obtained by heat treatment at 650°C for 8 hours under an acetylene atmosphere.

[0161] Physicochemical tests revealed that the material has a particle size of 8.3 μm and a specific surface area of ​​1.24 m². 2 / g, the true density of helium is 1.54g / cm³.3 .

[0162] Example 8

[0163] This embodiment provides a bismuth-supported material with a silicon oxide-based framework, which differs from Embodiment 1 in that: the Bi metal mass content is 50%, the SiO2 mass content is 45%, and the carbon layer content is 5%. The preparation method is as follows:

[0164] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template solution.

[0165] Next, 5.2g of bismuth citrate was added, and after stirring for half an hour, it was transferred to a reaction vessel and reacted at 100°C for 24 hours to obtain seed crystals.

[0166] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0167] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0168] Finally, the silicon oxide-supported bismuth material was obtained by heat treatment at 650°C for 3 hours under an acetylene atmosphere.

[0169] Physicochemical tests revealed that the material has a particle size of 8.5 μm and a specific surface area of ​​1.87 m². 2 / g, the true density of helium is 1.23g / cm³. 3 .

[0170] Comparative Example 1 (Carbon Skeleton)

[0171] This comparative example provides a carbon-framework-supported bismuth material, with a Bi metal mass content of 80%, a C framework mass content of 18%, and a carbon layer content of 2%. The preparation method is as follows:

[0172] First, commercial-grade porous carbon with a particle size of 8μm was selected as the carrier;

[0173] Secondly, porous carbon was placed in a CVD reactor, and metallic bismuth was vaporized and mixed with nitrogen, and deposited at 500°C for 6 hours.

[0174] Then, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a carbon-framework-supported bismuth material.

[0175] Physicochemical tests revealed that the material has a particle size of 8 μm and a specific surface area of ​​0.83 m². 2 / g, the true density of helium is 1.82g / cm³. 3 .

[0176] Comparative Example 2 (Superior Optimization of Component Content)

[0177] This comparative example provides a silicon oxide-based framework-supported bismuth material, with a Bi metal content of 40% by mass, a SiO2 content of 58% by mass, and a carbon layer content of 2%. The preparation method is as follows:

[0178] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template solution.

[0179] Next, add 3g of bismuth citrate, stir for half an hour, transfer to a reaction vessel, and react at 100°C for 24 hours to obtain seed crystals;

[0180] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0181] Then, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain the bismuth-based semi-finished product.

[0182] Finally, under an acetylene atmosphere, the material was heat-treated at 650°C for 2 hours to obtain a silicon oxide-supported bismuth material.

[0183] Physicochemical tests revealed that the material has a particle size of 5.2 μm and a specific surface area of ​​0.51 m². 2 / g, the true density of helium is 3.3g / cm³. 3 .

[0184] Comparative Example 3 (without carbon coating)

[0185] This comparative example provides a silicon oxide-based framework-supported bismuth material, with a Bi metal content of 80% and a SiO2 content of 20%, and the preparation method is as follows:

[0186] First, weigh 20 g of CTAB, add 1 L of deionized water and 300 mL of ethanol, place in a 35°C water bath, and stir vigorously for 1 hour until the CTAB is completely dissolved to form a clear solution. Then add 5 g of sodium metasilicate, adjust the pH to 11 with dilute sulfuric acid, and continue stirring for 1 hour to obtain the template solution.

[0187] Next, add 18g of bismuth citrate, stir for half an hour, transfer to a reaction vessel, and react at 100°C for 24 hours to obtain seed crystals;

[0188] Then, the seed crystals were filtered and washed. After confirming that there were no sodium ions remaining in the washing solution, the seed crystals were placed in air and calcined at 550°C for 2 hours to obtain the bismuth-based precursor.

[0189] Finally, the bismuth-based precursor was heat-treated at 700°C for 2 hours in a carbon monoxide atmosphere, and then heat-treated at 800°C under vacuum for 2 hours to obtain bismuth-supported silicon oxide material.

[0190] Physicochemical tests revealed that the material has a particle size of 8.1 μm and a specific surface area of ​​0.82 m². 2 / g, the true density of helium is 1.78g / cm³. 3 .

[0191] Electrode and half-cell preparation and electrochemical performance testing:

[0192] Using the negative electrode materials prepared in the above embodiments and comparative examples as negative electrode active materials, negative electrode sheets were prepared respectively. The electrode sheet composition was as follows: active material: 95%, binder SBR: 2%, conductive agent SP: 2.8%, and SWCNT: 0.2%. CR2032 coin cells were prepared using conventional methods for the negative electrode sheets, and the electrical performance of the cells was tested. The specific testing methods were as follows:

[0193] Half-cell assembly: Assemble CR2032 coin cells in a glove box, using lithium metal sheets as the counter electrode, polypropylene microporous membranes as the separator, and LiPF6 dissolved in a mixture of ethyl carbonate (EC) and diethyl carbonate (DEC) (volume ratio EC:DEC=1:1), with a LiPF6 concentration of 1 mol / L.

[0194] The battery was charged and discharged using the LAND battery testing system;

[0195] Rate testing: After the CR2032 button cell is left to stand for 6 hours, it is discharged at 0.1C to 0.005V, then discharged at a constant voltage of 0.005V until the current is cut off. After standing for 5 minutes, it is charged at 0.1C to 1.5V. After standing for 5 minutes, it is discharged at 1C to 0.05V. The 1C rate is calculated as: 1C discharge to 0.05V capacity / 0.1C charge to 1.5V capacity.

[0196] Charge transfer resistance test: After the CR2032 button cell was left to stand for 6 hours, it was discharged at 0.1C to 0.005V, then discharged at a constant voltage of 0.005V until the current was cut off. After standing for 5 minutes, it was charged at a constant current of 0.1C for 5 hours. After standing for 5 minutes, the charge transfer resistance Rct was tested using an electrochemical workstation.

[0197] Electrode expansion rate: After the CR2032 coin cell was left to stand for 6 hours, it was discharged at 0.05 C to 0.005 V, and then discharged at 0.01 C to 0.005 V. The coin cell was then disassembled in a glove box, the electrode was cleaned with DMC, and the electrode thickness was measured. The expansion rate was calculated as: (Initial fully charged electrode thickness - fresh electrode thickness) / fresh electrode thickness × 100%.

[0198] Cyclic test: After the CR2032 button battery is left to stand for 6 hours, it is discharged at 0.1C to 0.005V, then discharged at a constant voltage of 0.005V until the current is 0 and cut off, then charged at 0.5C to 1.5V, then discharged at 0.5C to 0.05V, and repeated 20 times.

[0199] The data obtained from the above embodiments and comparative examples are shown in Table 1 below.

[0200] Table 1

[0201]

[0202] According to the data in Table 1, Examples 1-8 are bismuth materials supported on a silicon oxide-based framework, Comparative Example 1 uses a carbon framework for vapor deposition to support bismuth, Comparative Example 2 has an excessively low bismuth loading and a high proportion of silicon oxide framework, and Comparative Example 3 does not have a carbon layer coating. From the data comparison, it can be seen that within the preferred scope of the present invention, the bismuth metal anode supported on a hollow, three-dimensional, interconnected silicon oxide-based framework constructed by thermal reduction has a strong mechanical confinement and confinement effect, as well as provides an ideal channel for the rapid transport of electrons and ions. These factors together endow the material with excellent rate performance and cycle stability.

[0203] Specifically, Examples 1-6 exhibit diversity in bismuth mass fraction (68-80 wt%), framework composition (pure SiO2 or doped with Al, Ti, Mg, etc.), and hollow structure, resulting in excellent overall electrochemical performance. With decreasing bismuth content and the introduction of metal elements for regulation, the electrode expansion rate remains low, significantly lower than the 125% of Comparative Example 1, indicating that the silicon oxide-based rigid framework combined with three-dimensional through-holes effectively alleviates volume expansion. In Example 6, the smaller hollow size (R1 = 32-107 nm) and optimized structure result in the strongest confinement effect and the lowest expansion rate. In all examples, Rct remains between 11-41 Ω, 1C rate retention is 65%-81%, and cycle retention reaches 87%-96%, demonstrating efficient ion / electron transport and good structural stability. Although Examples 7 and 8 are at the parameter boundary (Bi 50 wt%, carbon layer up to 15 wt%), the cycle retention rate is still over 90% (including 90%), and the expansion rate is 32%-38%, which is significantly better than the comparative examples. This proves that the structure of the present invention has excellent volume suppression ability and cycle stability over a wide composition range.

[0204] in, Figures 2-12 The images shown are SEM images of Examples 1-8 and Comparative Examples 1-3, respectively. The silicon oxide-based framework-supported Bi material provided by this invention is a bulk material with bismuth metal distributed within the framework channels. Figure 13 XRD characterization revealed that the grain size of the Bi particles in the silicon oxide-based framework-supported Bi material at approximately 27.4° was 17.6 nm, confirming that the bismuth particles of this invention are nanocrystalline, with a preferred grain size of 1-20 nm for the first characteristic peak. Figures 10-12 It can be seen that the comparative samples outside the specified range have rough surfaces and porous structures that cause excessive electrolyte wetting, leading to a decrease in cycle life.

[0205] 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silicon oxide-based framework-supported bismuth material, characterized in that, The material has a porous structure formed by internal hollow regions, and the porous structure is a three-dimensional interconnected nanopore network; wherein bismuth is disposed on the inner wall surface of the three-dimensional interconnected pores. The method for preparing the silicon oxide-based framework-supported bismuth material includes the following steps: constructing a micelle template with a surfactant and introducing silicate and bismuth source, obtaining a precursor by crystallization and calcination, then precipitating bismuth through thermal reduction to form a three-dimensional through-hole structure, and finally performing carbon coating in a carbon source atmosphere to obtain the silicon oxide-based framework-supported bismuth material. The general structural formula of the bismuth-supported bismuth material on the silicon oxide framework is Bi / SiM. a O b @C; SiM a O b A silicon-based oxide framework is used to support bismuth metal, M includes one or more of Al, Ti and Mg, 0≤a≤2, 0<b≤3; Bi metal nanoparticles are deposited on the pore walls. R2 is half the average of the maximum and minimum lengths of the primary particles passing through the midpoint in the two-dimensional plane, where 1 nm ≤ R2 ≤ 50 nm and the deposition thickness is L1, where 1 nm ≤ L1 ≤ 50 nm. C is a carbon coating layer with a thickness of L2, where 1 nm ≤ L2 ≤ 10 nm.

2. The silicon oxide-based framework-supported bismuth material according to claim 1, characterized in that, The number of hollow cells is N, where N≥1; The hollow dimension of the silicon oxide-based framework-supported bismuth material is R1, which is half the average of the maximum and minimum lengths passing through the midpoint in the two-dimensional plane, where 25 nm ≤ R1 ≤ 500 nm. The bismuth-loaded material on the silicon oxide-based framework is in bulk form.

3. The silicon oxide-based framework-supported bismuth material according to claim 1, characterized in that, The Bi metal is obtained by thermal reduction of bismuth oxide. The mean of the maximum and minimum lengths of bismuth oxide passing through the midpoint in the two-dimensional plane is R3, and 25 nm ≤ R3 ≤ 500 nm.

4. The silicon oxide-based framework-supported bismuth material according to claim 1, characterized in that, The mass fraction of bismuth in the silicon oxide-based framework-supported bismuth material is W1, where W1 is based on the total mass of the silicon oxide-based framework-supported bismuth material, and 50 wt% ≤ W1 < 100 wt%. The bismuth-supported bismuth material on the silicon oxide framework contains SiM a O b The mass fraction is W2, where W2 is based on the total mass of the bismuth material supported on the silicon oxide framework, and W2 ≤ 50 wt%. The mass fraction of the carbon layer in the silicon oxide-based framework-supported bismuth material is W3, and W3 is based on the total mass of the silicon oxide-based framework-supported bismuth material, with W3 ≤ 15wt%.

5. The silicon oxide-based framework-supported bismuth material according to claim 1, characterized in that, The specific surface area of ​​the bismuth-supported bismuth material on the silicon oxide framework is 0.1-10 m². 2 / g; The particle size D50 of the bismuth material supported on the silicon oxide framework is 0.1-10 μm; The helium true density of the silicon oxide-based framework-supported bismuth material is 1-5 g / cm³. 3 .

6. The silicon oxide-based framework-supported bismuth material according to claim 1, characterized in that, The method for preparing the silicon oxide-based framework-supported bismuth material includes the following steps: Step S1: Mix the surfactant with water and stir to form a micelle solution. Then add a silicate solution, adjust the pH with dilute acid, and stir to obtain a template agent solution. Step S2: Add bismuth source to the template agent preparation solution, stir, and then place it in a reaction vessel to crystallize and obtain seed crystals; Step S3: After calcining the seed crystal in air, a bismuth-based precursor is obtained; Step S4: The bismuth-based precursor is subjected to reduction heat treatment and vacuum heat treatment in sequence to obtain a semi-finished product; Step S5: Place the semi-finished product in a carbon source atmosphere for carbon coating to obtain a silicon oxide-based framework supported bismuth material.

7. The silicon oxide-based framework-supported bismuth material according to claim 6, characterized in that, In step S1, the stirring temperature is 30-60℃ and the pH is 9.5-11.5; The surfactant includes hexadecyltrimethylammonium bromide; The silicate includes sodium metasilicate; The dilute acid includes sulfuric acid; In step S2, the reaction temperature in the reactor is 80-120℃; The bismuth source in step S2 includes at least one of bismuth trioxide and bismuth citrate; In step S3, the calcination temperature is 400-600℃; In step S4, the temperatures of the reduction heat treatment and the vacuum heat treatment are 500-1000℃; In step S4, the reducing atmosphere of the reduction heat treatment includes carbon monoxide; In step S5, the carbon coating temperature is 400-1000℃; In step S5, the carbon source atmosphere includes acetylene.

8. The application of the silicon oxide-based framework-supported bismuth material as described in any one of claims 1-7 in the preparation of lithium-ion battery anodes.

9. A lithium-ion battery, characterized in that, The active material used in the negative electrode of the lithium-ion battery includes the silicon oxide-based framework supported bismuth material as described in any one of claims 1-7.

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