Silicon-carbon material with sandwiched hollow core-shell and preparation method thereof

Abstract

The present application relates to a kind of sandwich hollow core-shell type silicon-carbon materials and its preparation method, sandwich hollow core-shell type silicon-carbon material is nanometer silicon powder as core, with carbon black as shell, with mass fraction, carbon black:40~98 parts;Nanometer silicon powder:2~60 parts.Sandwich hollow core-shell type silicon-carbon material in the present application can be efficiently, low-costly prepared by the method in the present application.

Description

Technical Field

[0001] This invention relates to the field of silicon-carbon materials, specifically to a sandwich-type hollow core-shell silicon-carbon material and its preparation method. Background Technology

[0002] Silicon materials used in lithium-ion battery anodes form silicon-lithium alloys with lithium, achieving a theoretical specific capacity of up to 3572 mA·h / g, far exceeding the theoretical specific capacity of commercial graphite (372 mA·h / g). However, the alloying process between silicon and lithium results in a silicon volume expansion rate as high as 270%, which easily leads to silicon pulverization, causing electrode structure instability and failure. This results in electrode structure collapse and active material peeling, leading to a significant decrease in electrode capacity or even complete failure. Carbonaceous anode materials are commonly used in batteries, such as graphite and mesophase microspheres. They exhibit relatively small volume changes during charge and discharge; for example, graphite has a volume expansion rate of 10.6%, demonstrating good cycle stability and conductivity. Furthermore, silicon and carbon have similar chemical properties, allowing them to bond tightly, which can improve the silicon volume effect and significantly enhance its electrochemical stability. Chinese patent CN 105304874B discloses a method for preparing a sandwich-type hollow double-layer carbon / silicon composite lithium-ion battery anode material. This invention employs an etching method, using phenolic resin and dopamine as carbon sources, a mixed solution of ethanol / water as a solvent, and silica as a hard template. Through precise calculations and control of synthesis parameters, a double-layer carbon / silicon composite nanomaterial with a sandwich hollow structure is prepared.The preparation steps are as follows: a. Disperse nano-silicon powder uniformly in deionized water at a mass-to-volume ratio of 1:2 mg / mL. Add a mixture of ethanol and 25-28 wt.% ammonia, where the volume ratio of ethanol to ammonia is 20:1. Stir for 5 min, then add tetraethyl orthosilicate (TEOS). Stir at 30 °C for 6 h, centrifuge, wash, and dry to obtain the product Si@SiO2; b. Add 25-28 wt.% ammonia to a mixture of ethanol and deionized water at a volume ratio of 2:1, where the volume ratio of the mixture to ammonia is 30:1. Mix thoroughly and stir at 30 °C for 0.5 h. Add the Si@SiO2 powder obtained in step a, making the mass-to-volume ratio of Si@SiO2 powder to the mixture 10.5 mg / mL. Then add resorcinol and 37 wt.% formaldehyde solution, and stir for 24 min. h. Place the product into a 50 mL autoclave lined with polytetrafluoroethylene and react at 100 °C for 18–24 h. After centrifugation, washing, and drying, obtain Si@SiO2@RF powder. c. Disperse the Si@SiO2@RF powder uniformly in deionized water at a mass-to-volume ratio of 7:4 mg / mL. Add a mixture of ethanol and 25–28 wt.% ammonia water, with a volume ratio of ethanol to ammonia water of 20:1. Stir for 5 min, then add tetraethyl orthosilicate (TEOS). Stir at 30 °C for 6 h, centrifuge, wash, and dry to obtain the product Si@SiO2@RF@SiO2. d. Dissolve the Si@SiO2@RF@SiO2 powder obtained in step c and dopamine hydrochloride (PDA) powder completely in a borax buffer solution at pH = 9.18 at a mass ratio of 3:1. Stir at room temperature for 24 min. h; then wash and dry to obtain Si@SiO2@RF@SiO2@PDA. Calcine this powder at 600-900 °C for 2-3 h under an inert atmosphere to obtain the product Si@SiO2@C@SiO2@C; e. Add the Si@SiO2@C@SiO2@C powder obtained in step d to a 0.5-3 wt.% HF solution for etching for 1-30 min. After etching, the product is centrifuged, washed, and dried to obtain a sandwich-type hollow double-layer carbon / silicon composite nanomaterial. This process is relatively complex, inefficient, and uses HF acid, resulting in poor environmental friendliness, making it unsuitable for large-scale production.

[0003] Chinese patent CN110828814B discloses a sandwich-structured hollow double-shell silicon-carbon-graphene electrode material, its preparation method, and its application. The material has the following structure: sandwich-structured hollow double-shell silicon-carbon particles are fixed on reduced-oxidation graphene sheets. The silicon-carbon particles have a nano-silicon core, a SiOx layer on the surface, and a carbon layer on the outermost layer. A hollow layer exists between the SiOx layer and the carbon layer. The thickness of the SiOx layer is 0.1-1 nm, the thickness of the carbon layer is 0.2-2 nm, and the thickness of the hollow layer is 2-10 nm. The preparation method is as follows: a SiOx layer is formed on the surface of the nano-silicon, which is then dispersed in a polydiallyldimethylammonium chloride solution for adsorption, and the solid particles are separated. The solid particles are then added to a graphene oxide solution, stirred, separated, and dried. Subsequently, the solid undergoes hydrogenation reduction, acid washing, and drying to obtain the sandwich-structured hollow double-shell silicon-carbon-graphene electrode material with nano-silicon particle sizes of 20-100 nm. This process is time-consuming, costly, and less competitive in the market. Furthermore, it uses acid, making it less environmentally friendly.

[0004] Chinese patent CN113644251B discloses a hollow silicon-carbon anode material and its preparation method, comprising a silicon core and a graphene outer layer coating the outer surface of the silicon core, with a hollow layer disposed between the silicon core and the graphene outer layer. The preparation steps are as follows: Step (A): Dissolve the silicon core in a metal solution, add an alkali to react, stir, centrifuge and wash with water to obtain a first composite particle with metal deposit coating the silicon core; Step (B): Add an organic substance to the first composite particle and condense it under acidic conditions, centrifuge and wash with water to obtain a second composite particle with an organic ester coating the silicon core; Step (C): Heat and calcine the second composite particle under inert gas protection to graphitize the organic ester to form a graphene outer layer, cool to obtain a third composite particle; Step (D): React the third composite particle under acidic conditions to remove the metal deposit and form a hollow layer to obtain a hollow silicon-carbon anode material; wherein, the metal solution in step (A) is a zinc chloride solution, and the organic substance in step (B) is isopropanol stearate. This invention provides a hollow silicon-carbon anode material that can provide space for the expansion of silicon materials, effectively alleviating the capacity decay problem caused by the expansion of silicon-carbon anode materials during charging and discharging. This process uses acid to remove metal, which is less environmentally friendly.

[0005] In summary, the preparation of core-shell silicon-carbon materials with hollow structures all involve using metal as a template agent, followed by high-temperature carbonization to form a core-shell structure, and then removing the metal by acid washing to form a core-shell silicon-carbon material with a hollow structure. The production process is intermittent, lengthy, cumbersome, inefficient, environmentally unfriendly, and costly. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a sandwich hollow core-shell silicon-carbon material that can be prepared on a large scale, efficiently and at low cost.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is: a sandwiched hollow core-shell silicon-carbon material, which uses nano-sized silicon powder as the core and carbon black as the shell, and by mass parts, carbon black: 40~98 parts; nano-sized silicon powder: 2~60 parts.

[0008] Furthermore, carbon black is amorphous carbon.

[0009] This invention also provides a method for preparing a sandwich-type hollow core-shell silicon-carbon material, which is carried out in a reactor. The reactor includes a combustion chamber, a throat section, a reaction section, and a quenching section arranged sequentially. The preparation method includes:

[0010] S1. Introduce the combustion oil into the combustion chamber. After the combustion chamber temperature is adjusted to 1500~1700℃, introduce the silica powder solvent dispersion into the front of the combustion chamber from the side. At this time, the temperature drops to 1300~1400℃.

[0011] S2, the cavity additive aqueous solution is introduced into the front of the combustion chamber from the side, and the temperature drops to 1000~1100℃;

[0012] S3, the well-mixed raw material oil is introduced into the rear of the combustion chamber, at which point the temperature drops to 800~900℃;

[0013] S4, the reaction section is heated to 1400~1500℃, and the temperature drops to 1000~1100℃ after the feed oil passes through;

[0014] S5, Add the particle size control agent aqueous solution to the reactor;

[0015] S6, add quench water in the quench section to reduce the temperature to below 240℃, and separate to obtain silicon-carbon material containing cavity additive and particle size control agent;

[0016] S7. The silicon-carbon material containing cavity additives and particle size control agents is dispersed in hot water at 50~60℃, stirred, and filtered using a plate and frame filter. This operation is repeated at least once. When the magnesium and potassium content is lower than 40ppm, it is dispersed in water and spray-dried at a temperature of 160~180℃. Then it is dried until the heat loss is less than 1wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material is obtained.

[0017] Furthermore, the preparation method of the silica powder solvent-based dispersion includes:

[0018] First, add the oily dispersant and grinding resin to the solvent under high-speed stirring. After stirring evenly, slowly add the nano-sized silicon powder and stir for 30-60 minutes to obtain a pre-dispersion of silicon powder. Then, grind the pre-dispersion of silicon powder to a fineness of 0.3-3μm to obtain a solvent-based dispersion of silicon powder.

[0019] Furthermore, the nano-sized silicon powder is obtained by mechanical grinding, and the particle size of the nano-sized silicon powder is 0.1~0.9μm;

[0020] And / or the silica powder solvent-based dispersion contains 20~30 wt.% nano-sized silica powder.

[0021] And / or the silica powder solvent-based dispersion contains 2~6 wt.% oily dispersant;

[0022] The content of grinding resin in the silicon powder solvent-based dispersion is 40~50 wt.%;

[0023] And / or the silica powder solvent dispersion contains 14~38 wt.% solvent.

[0024] Furthermore, the oily dispersant is at least one of the following: modified polyester polymer solution, modified polyurethane polymer, polyester-modified polyphosphate compound, unsaturated polyamide carboxylate, and high molecular weight unsaturated carboxylic acid;

[0025] And / or the solvent is at least one of solvent oil, turpentine, toluene, and xylene;

[0026] And / or the abrasive resin is a solvent-based abrasive resin, comprising at least one of acrylic resin, phenolic resin, and alkyd resin.

[0027] Furthermore, the combustion oil is ethylene tar;

[0028] The feedstock oil is at least one of clarified oil, anthracene oil, ethylene tar and coal tar, and the amount used is 1.6 to 1.7 times the mass of carbon black (based on data accumulated from the production line).

[0029] Furthermore, the particle size control agent is at least one of potassium carbonate, potassium oxide, and potassium hydroxide. The feed location of the particle size control agent aqueous solution is anywhere in the reaction section and the quenching section. The dosage of the particle size control agent is 1-3 wt.% of the hollow core-shell silicon carbide material in the sandwich layer after demagnetization, and the solid content in the particle size control agent aqueous solution is 10-20 wt.%. The quality of the hollow core-shell silicon carbide material in the sandwich layer after demagnetization is obtained based on long-term data accumulation of the production line, and the yield of carbon generated from the feed oil is approximately 58%-63%.

[0030] Furthermore, the cavity additive is magnesium sulfate, and the amount of cavity additive is 20-30 wt.% of the silicon powder mass. The aqueous solution of the cavity additive contains 10-20 wt.% magnesium sulfate.

[0031] By adopting the above technical solution, the sandwich hollow core-shell silicon-carbon material of the present invention uses nano-sized silicon powder as the core, a hollow additive, and raw material oil as the carbon source. Amorphous carbon black is formed by high-temperature pyrolysis and condensation to form the shell. A particle size control agent is used as the main method for controlling particle size, supplemented by the particle size control agent feeding position. The combination of these two methods allows for precise control of the particle size of the sandwich hollow core-shell silicon-carbon material. Finally, the particle size control agent and the hollow additive are removed through a water washing process to obtain the sandwich hollow core-shell silicon-carbon material. The preparation method of the sandwich hollow core-shell silicon-carbon material of the present invention has high production efficiency, short process flow, and low cost. Simultaneously, the sandwich hollow core-shell silicon-carbon material exhibits very high initial charge-discharge specific capacity, initial coulombic efficiency, and cycle stability. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the reactor used in the sandwich-type hollow core-shell silicon-carbon material of the present invention.

[0033] Figure 2 This is a structural diagram of the combustion chamber of the present invention from another perspective;

[0034] Figure 3 This is a schematic diagram of the preparation process of the sandwich hollow core-shell silicon-carbon material of the present invention;

[0035] Figure 4 This is a SEM image of the silicon powder used in this invention;

[0036] Figure 5 This is a SEM image of silicon powder after it has melted at high temperature.

[0037] Figure 6 This is a TEM image of the state in step S1 of the preparation method of the sandwich hollow core-shell silicon-carbon material of the present invention.

[0038] Figure 7 This is a TEM image of the carbon layer in step S1 of the sandwich hollow core-shell silicon-carbon material of the present invention.

[0039] Figure 8 This is a SEM image of the sandwich hollow core-shell silicon-carbon material of the present invention;

[0040] Figure 9 The sandwich hollow core-shell silicon-carbon material of the present invention Figure 8 Enlarged image;

[0041] In the diagram, 1 is the combustion oil feed pipe; 2 is the silicon powder solvent dispersion feed point; 3 is the cavity additive aqueous solution feed point; 4 is the combustion chamber; 5 is the throat section; 6 is the raw material oil feed pipe; 7 is the reaction section; 8 is the quench section; a represents the state of silicon powder; b represents the state after step S1; c represents the state after step S2; d represents the state after step S5; and e represents the state after step S7. Detailed Implementation

[0042] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0043] like Figure 2 As shown, a sandwich hollow core-shell silicon-carbon material has nano-sized silicon powder as the core and carbon black as the shell. By mass, carbon black: 40~98 parts; nano-sized silicon powder: 2~60 parts.

[0044] In this embodiment, the carbon black is amorphous carbon.

[0045] The above-mentioned method for preparing sandwich-structured hollow core-shell silicon-carbon materials is carried out in a reactor, such as... Figure 1 , 2 As shown, the reactor can be an oil furnace soft carbon black reactor, including a combustion chamber 4, a throat section 5, a reaction section 7, and a quenching section 8 arranged sequentially; the preparation method includes:

[0046] S1, the combustion oil is introduced into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1500~1700℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1300~1400℃.

[0047] S2, the cavity additive aqueous solution is introduced from the side into the front of the combustion chamber 4 through the cavity additive aqueous solution feed port 3, and the temperature drops to 1000~1100℃;

[0048] S3, the well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops to 800~900℃;

[0049] S4, the reaction section is heated to 1400~1500℃, and the temperature drops to 1000~1100℃ after the feed oil passes through;

[0050] S5, Add the particle size control agent aqueous solution to the reactor;

[0051] S6, add quench water to the quench section 8 to reduce the temperature to below 240℃, and separate the silicon-carbon material containing cavity additive and particle size control agent.

[0052] S7. Disperse the silicon-carbon material containing cavity additives and particle size control agents in hot water at 50~60℃. The content of the core-shell silicon-carbon material containing cavity additives and particle size control agents is 8~10wt.%. Stir for 1 hour and filter with plate and frame filter. Repeat this operation at least once. When the magnesium and potassium content is lower than 40ppm, disperse in water and spray dry at a temperature of 160-180℃. Then dry until the heat loss is less than 1wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material is obtained.

[0053] Specifically, the production process uses fuel oil as the fuel, and a high-speed blower provides a slight excess of air to ensure complete combustion of the fuel oil, raising the temperature of combustion chamber 4 to 1500~1700℃. At this point, turbulent rotating air is formed inside the combustion chamber. Then, a silicon powder solvent-based dispersion is introduced into the side of combustion chamber 4, at which point the temperature drops to 1300~1400℃. Some of the solvent will combine with the oxygen in combustion chamber 4 and burn off, while most of it will decompose to form carbon coating on the silicon surface. At this temperature, the irregular silicon powder will become more rounded. Then, a room-temperature cavity additive aqueous solution is introduced into the side of combustion chamber 4. Under the influence of turbulent rotating wind, a more uniform environment is formed inside combustion chamber 4. When the room-temperature cavity additive aqueous solution is added to the system, the system temperature drops significantly to 1000~1100℃. The water instantly turns into water vapor, while a large amount of cavity additive becomes a solid and adheres to the surface of silicon powder. Then, feedstock oil is introduced into the rear of combustion chamber 4. The carbon formed by cracking coats the outside of the cavity additive. The high-temperature cracking of the feedstock oil further lowers the system temperature. Therefore, in order to improve the cracking efficiency, the reaction temperature needs to be increased in the reaction section. Some of the feedstock oil cracks and forms a carbon layer on the surface of magnesium sulfate, while most of the original carbon spheres formed by cracking of the feedstock oil surround the silicon surface or form aggregates or attachments. Finally, a particle size control agent solution is added. It is in a molten state at high temperature. At this time, the particle size control agent coats the surface of silicon carbon particles, preventing the carbon spheres from coating the silicon particles, thus preventing the particle size of silicon carbon material from continuing to increase, thereby achieving the purpose of precise control of silicon carbon material particle size. The sandwich-type hollow core-shell silicon-carbon material of this invention uses nano-sized silicon powder as the core, water-soluble inorganic salt as the hollowing agent, and raw oil as the carbon source. Amorphous carbon black is formed by high-temperature pyrolysis and condensation to form the shell. A particle size control agent is used as the primary method for controlling particle size, supplemented by the particle size control agent's feeding position. The combination of these two methods allows for precise control of the silicon-carbon material's particle size. Finally, a water washing process removes the particle size control agent and the hollowing agent, yielding the sandwich-type hollow core-shell silicon-carbon material. The preparation method of the sandwich-type hollow core-shell silicon-carbon material of this invention features high production efficiency, a short process flow, and low cost. Simultaneously, the sandwich-type hollow core-shell silicon-carbon material exhibits very high initial charge-discharge specific capacity, initial coulombic efficiency, and cycle stability.

[0054] In this embodiment, the method for preparing the silicon powder solvent-based dispersion includes:

[0055] First, add the nonionic dispersant and grinding resin to the solvent under high-speed stirring. After stirring evenly, slowly add the nano-sized silicon powder and stir for 30-60 minutes to obtain a pre-dispersion of silicon powder. Then, grind the pre-dispersion of silicon powder to a fineness of 0.3-3μm to obtain a solvent-based dispersion of silicon powder.

[0056] In this embodiment, the nano-sized silicon powder is obtained by mechanical grinding, and the particle size of the nano-sized silicon powder is 0.1~0.9μm;

[0057] And / or the silica powder solvent-based dispersion contains 20~30 wt.% nano-sized silica powder.

[0058] And / or the silica powder solvent-based dispersion contains 2~6 wt.% oily dispersant;

[0059] The content of grinding resin in the silicon powder solvent-based dispersion is 40~50 wt.%;

[0060] And / or the silica powder solvent dispersion contains 14~38 wt.% solvent.

[0061] In this embodiment, the oily dispersant is at least one of the following: modified polyester polymer solution, modified polyurethane polymer, polyester-modified polyphosphate compound, unsaturated polyamide carboxylate, and high molecular weight unsaturated carboxylic acid.

[0062] And / or the solvent is at least one of solvent oil, turpentine, toluene, and xylene;

[0063] And / or the abrasive resin is a solvent-based abrasive resin, comprising at least one of acrylic resin, phenolic resin, and alkyd resin.

[0064] In this embodiment, the combustion oil is ethylene tar;

[0065] The feedstock oil is at least one of clarified oil, anthracene oil, ethylene tar and coal tar, and the amount used is 1.6 to 1.7 times the mass of carbon black (based on data accumulated from the production line).

[0066] In this embodiment, the particle size control agent is at least one of potassium carbonate, potassium oxide and potassium hydroxide. The feed location of the particle size control agent aqueous solution is any location in the reaction section and the quenching section 8. The amount of particle size control agent is 1 to 3 wt.% of the hollow core-shell silicon carbide material in the sandwich after demagnetization. The solid content in the particle size control agent aqueous solution is 10 to 20 wt.%.

[0067] In this embodiment, the cavity additive is magnesium sulfate, and the amount of cavity additive is 20-30 wt.% of the silicon powder mass. The aqueous solution of the cavity additive contains 10-20 wt.% magnesium sulfate.

[0068] The technical solutions involved in the above embodiments will be described in detail below with reference to specific examples and comparative examples.

[0069] Example 1

[0070] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0071] Carbon black: 90 parts;

[0072] 10 parts of nano-sized silicon powder with a particle size of 0.2 μm.

[0073] Preparation of silica powder solvent-based dispersions:

[0074] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0075] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0076] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0077] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0078] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0079] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0080] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0081] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0082] Example 2

[0083] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0084] Carbon black: 80 parts;

[0085] Nanoscale silicon powder with a particle size of 0.2μm: 20 parts.

[0086] Preparation of silica powder solvent-based dispersions:

[0087] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0088] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0089] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0090] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0091] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0092] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0093] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0094] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0095] Example 3

[0096] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0097] Carbon black: 70 parts;

[0098] Nanoscale silicon powder with a particle size of 0.2μm: 30 parts.

[0099] Preparation of silica powder solvent-based dispersions:

[0100] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0101] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0102] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0103] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0104] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0105] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0106] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0107] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0108] Example 4

[0109] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0110] Carbon black: 80 parts;

[0111] Nanoscale silicon powder with a particle size of 0.5μm: 20 parts.

[0112] Preparation of silica powder solvent-based dispersions:

[0113] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.5-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0114] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0115] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0116] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0117] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0118] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0119] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0120] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0121] Example 5

[0122] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0123] Carbon black: 80 parts;

[0124] Nanoscale silicon powder with a particle size of 0.2μm: 20 parts.

[0125] Preparation of silica powder solvent-based dispersions:

[0126] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0127] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0128] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0129] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0130] The reaction section is heated to 1400℃, and the temperature drops to 1000℃ after the feed oil passes through.

[0131] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0132] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0133] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0134] Comparative Example 1

[0135] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0136] Carbon black: 100 parts;

[0137] Nanoscale silicon powder with a particle size of 0.2μm: 0 parts;

[0138] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0139] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0140] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0141] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0142] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0143] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0144] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0145] Comparative Example 2

[0146] Carbon black: 80 parts;

[0147] Nanoscale silicon powder with a particle size of 2μm: 20 parts.

[0148] Preparation of silica powder solvent-based dispersions:

[0149] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 4 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0150] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0151] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0152] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0153] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0154] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0155] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate and potassium oxide.

[0156] The sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was dispersed in hot water at 50-60°C. The content of the sandwiched core-shell silicon-carbon material containing magnesium sulfate and potassium oxide was 10 wt.%. The mixture was stirred for 1 hour, filtered by plate and frame filter, and the magnesium and potassium contents were measured. If the content was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material was obtained.

[0157] Comparative Example 3

[0158] The sandwich-structured hollow core-shell silicon-carbon material comprises the following components:

[0159] Carbon black: 80 parts;

[0160] Nanoscale silicon powder with a particle size of 0.2μm: 20 parts.

[0161] Preparation of silica powder solvent-based dispersions:

[0162] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0163] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0164] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0165] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0166] A 10 wt.% potassium oxide aqueous solution was added to the front of the quenching section 8. The amount of potassium oxide was 3 wt.% of the mass of the hollow core-shell silicon-carbon sandwich layer after demagnetization.

[0167] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing potassium oxide.

[0168] The prepared potassium oxide-containing sandwich core-shell silicon carbide material was dispersed in hot water at 50-60°C. The potassium oxide content of the sandwich core-shell silicon carbide material was 10 wt.%. After stirring for 1 hour, the mixture was filtered using a plate and frame filter, and the potassium content was measured. If it was less than 40 ppm, it could be dispersed in water. The mixture was then spray-dried at 170°C and dried a second time until the heat loss was less than 1 wt.%. After demagnetization, the sandwich hollow core-shell silicon carbide material was obtained.

[0169] Comparative Example 4

[0170] Carbon black: 80 parts;

[0171] Nanoscale silicon powder with a particle size of 0.2μm: 20 parts.

[0172] Preparation of silica powder solvent-based dispersions:

[0173] 4 wt.% of modified polyester polymer solution oil dispersant and 40 wt.% of phenolic grinding resin in a silica powder solvent dispersion were added to a high-speed stirred tank containing 26 wt.% toluene solution. After stirring evenly, 30 wt.% of 0.2-micron silica powder was slowly added to the toluene solution. After stirring for 60 minutes, a pre-dispersed silica powder toluene dispersion was obtained. The pre-dispersed silica powder toluene dispersion was then introduced into a horizontal sand mill and ground to a fineness of D50 of 1 μm. The grinding was then stopped, and the silica powder solvent dispersion was obtained.

[0174] The combustion oil is fed into the combustion chamber 4 through the combustion oil feed pipe 1. After the temperature of the combustion chamber 4 is adjusted to 1600℃, the silicon powder solvent dispersion is introduced into the front of the combustion chamber 4 from the side through the feed port 2. At this time, the temperature drops to below 1400℃.

[0175] An aqueous solution of cavity additive containing 20 wt.% magnesium sulfate is introduced from the side into the front of combustion chamber 4 through feed inlet 3, and the temperature is reduced to 1100℃. The amount of cavity additive used is 20 wt.% of the silicon powder mass.

[0176] The well-mixed raw oil is introduced into the rear of the combustion chamber 4 through the raw oil feed pipe 6, at which point the temperature drops below 900℃;

[0177] The reaction section is heated to 1500℃, and the temperature drops to 1100℃ after the feed oil passes through.

[0178] In the quenching section 8, quench water is added to lower the temperature to below 240°C, and then the material enters the separation device to obtain a sandwich core-shell silicon-carbon material containing magnesium sulfate.

[0179] The prepared sandwich core-shell silicon-carbon material containing magnesium sulfate was dispersed in hot water at 50~60℃. The content of the magnesium sulfate sandwich core-shell silicon-carbon material was 10wt.%. After stirring for 1 hour, the mixture was filtered by plate and frame filter, and the magnesium content was measured. If it was less than 40ppm, it could be dispersed in water. The mixture was then spray-dried at 170℃ and dried a second time until the heat loss was less than 1wt.%. After demagnetization, the sandwich hollow core-shell silicon-carbon material was obtained.

[0180] Table 1: Basic properties of the sandwich hollow core-shell silicon-carbon materials prepared in Examples 1 to 5 and Comparative Examples 1 to 4.

[0181]

[0182] Among them, the differences in the composition of the sandwich hollow core-shell silicon carbon in Examples 1 to 3 lie in the fraction of silicon powder and carbon black, which leads to the performance differences of the sandwich hollow core-shell silicon carbon material; the difference between Example 4 and Examples 1 to 3 lies in the particle size of silicon powder; the difference between Example 5 and Examples 1 to 3 lies in the reaction temperature.

[0183] Comparative Example 1 is carbon black formed without the addition of silicon powder;

[0184] The difference in Comparative Example 2 is that the silicon powder used has a particle size of 2μm;

[0185] The difference in Comparative Example 3 is that no cavity additive was used;

[0186] The difference in Comparative Example 4 is that no particle size control agent was used;

[0187] The basic performance indicators of the sandwich hollow core-shell silicon-carbon material of the present invention are shown in Table 1. As can be seen from Table 1, silicon powder can significantly increase the specific capacity and coulombic efficiency of amorphous carbon materials, increasing the specific capacity by about 5 to 8 times and significantly increasing the coulombic efficiency by about 60 to 80%. At the same time, the specific capacity increases with the increase of silicon powder dosage, and the smaller the particle size of silicon powder, the higher the specific capacity.

[0188] The sandwich-structured hollow core-shell silicon-carbon material of this invention is produced using a soft oil furnace carbon black production line. Nanoscale silicon powder serves as the core, while ethylene tar, coal tar, and anthracene oil are used as carbon sources. These are pyrolyzed and condensed at high temperatures to form amorphous carbon black as the shell. A cavity-forming agent is used as the main auxiliary agent for creating the hollow core, and a particle size control agent is used as the primary method for controlling particle size. The particle size control agent's feeding position is also considered. The combination of these two methods allows for precise control of the silicon-carbon material's particle size. Finally, a water washing process removes the cavity-forming agent and the particle size control agent, yielding the sandwich-structured hollow core-shell silicon-carbon material. This sandwich-structured hollow core-shell silicon-carbon material, when used as a lithium-ion battery anode, can significantly increase the battery's specific capacity and improve its energy storage performance. When applied to new energy vehicles, it can significantly reduce consumers' range anxiety.

[0189] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a sandwich-type hollow core-shell silicon-carbon material, characterized in that, The sandwich hollow core-shell silicon-carbon material uses nano-sized silicon powder as the core and carbon black as the shell. By mass parts, carbon black: 40~98 parts; nano-sized silicon powder: 2~60 parts; carbon black is amorphous carbon. The preparation process takes place in a reactor, which includes a combustion chamber, a throat section, a reaction section, and a quenching section arranged sequentially. The preparation method includes: S1. Introduce the combustion oil into the combustion chamber. After the combustion chamber temperature is adjusted to 1500~1700℃, introduce the silica powder solvent dispersion into the front of the combustion chamber from the side. At this time, the temperature drops to 1300~1400℃. S2, the cavity additive aqueous solution is introduced into the front of the combustion chamber from the side, and the temperature drops to 1000~1100℃; S3, the well-mixed raw material oil is introduced into the rear of the combustion chamber, at which point the temperature drops to 800~900℃; S4, the reaction section is heated to 1400~1500℃, and the temperature drops to 1100~1200℃ after the feed oil passes through; S5, Add the particle size control agent aqueous solution to the reactor; S6, add quench water to the quench section to reduce the temperature to below 240℃, and separate to obtain core-shell silicon-carbon material containing cavity additives and particle size control agents; S7. Disperse the core-shell silicon-carbon material containing cavity additives and particle size control agents in hot water at 50~60℃, stir, and filter using a plate and frame filter. Repeat this operation at least once. When the magnesium and potassium content is less than 40ppm, disperse it in water and spray dry it at a temperature of 160~180℃. Then dry it until the heat loss is less than 1wt.%. After demagnetization, the sandwiched hollow core-shell silicon-carbon material is obtained. The preparation method of silica powder solvent-based dispersion includes: First, add the oily dispersant and grinding resin to the solvent under high-speed stirring. After stirring evenly, slowly add the nano-sized silicon powder and stir for 30-60 minutes to obtain a pre-dispersion of silicon powder. Then, grind the pre-dispersion of silicon powder to a fineness of 0.3-3μm to obtain a solvent-based dispersion of silicon powder.

2. The method for preparing sandwich-structured hollow core-shell silicon-carbon material according to claim 1, characterized in that, The nano-sized silicon powder is obtained by mechanical grinding, and the particle size of the nano-sized silicon powder is 0.1~0.9μm; And / or the silica powder solvent-based dispersion contains 20~30 wt.% nano-sized silica powder. And / or the silica powder solvent-based dispersion contains 2~6 wt.% oily dispersant; The content of grinding resin in the silicon powder solvent-based dispersion is 40~50 wt.%; And / or the silica powder solvent dispersion contains 14~38 wt.% solvent.

3. The method for preparing sandwich-structured hollow core-shell silicon-carbon material according to claim 1, characterized in that, The oily dispersant is at least one of the following: modified polyester polymer solution, modified polyurethane polymer, polyester-modified polyphosphate compound, unsaturated polyamide carboxylate, and high molecular weight unsaturated carboxylic acid; And / or the solvent is at least one of solvent oil, turpentine, toluene, and xylene; And / or the abrasive resin is a solvent-based abrasive resin, comprising at least one of acrylic resin, phenolic resin, and alkyd resin.

4. The method for preparing sandwich-structured hollow core-shell silicon-carbon material according to claim 1, characterized in that, The fuel is ethylene tar; The raw material oil is at least one of clarified oil, anthracene oil, ethylene tar and coal tar, and is used in an amount of 1.6 to 1.7 times the mass of carbon black, wherein the mass of carbon black is obtained based on data accumulated from the production line.

5. The method for preparing sandwich-structured hollow core-shell silicon-carbon material according to claim 1, characterized in that, The particle size control agent is at least one of potassium carbonate, potassium oxide and potassium hydroxide. The feed location of the particle size control agent aqueous solution is any place in the reaction section and the quenching section. The amount of particle size control agent is 1~3 wt.% of the hollow core-shell silicon carbide material in the sandwich after demagnetization. The solid content in the particle size control agent aqueous solution is 10~20 wt.%.

6. The method for preparing sandwich-structured hollow core-shell silicon-carbon material according to claim 1, characterized in that, The cavity additive is magnesium sulfate, and the amount of cavity additive is 20-30 wt.% of the silicon powder mass. The aqueous solution of the cavity additive contains 10-20 wt.% magnesium sulfate.

Images