High-power hard carbon composite material, preparation method thereof, and battery

Abstract

The present invention relates to the technical field of secondary battery materials, and discloses a high-power hard carbon composite material, a preparation method thereof, and a battery. The preparation process of the high-power hard carbon composite material is as follows: modified metal powder is prepared; the modified metal powder is blended and reacted with a saccharide compound, a crosslinking agent, and a magnetic oxide, filtered, dried, and carbonized to obtain a hard carbon material; the hard carbon material is blended and reacted with asphalt, an organic solvent, and an organic sodium salt, filtered, dried, and carbonized to obtain the high-power hard carbon composite material. The present invention improves the electronic conductivity and strength of the material by doping metal powder in the hard carbon core; changes the orientation of the carbon material by adding a magnetic oxide, improves the ion intercalation channels of the material, and further improves the power performance; coats the outer layer of the hard carbon composite material with sodium-doped amorphous carbon to reduce the irreversible capacity of the material, and improves the first efficiency, cycle performance, and high-temperature storage performance of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of secondary battery materials, and particularly to a high-power hard carbon composite material, a preparation method thereof, and a battery. Background Art

[0002] Hard carbon is an amorphous carbon that is difficult to graphitize. It has an interlaced layered structure with a large interlayer spacing, enabling lithium ions to be inserted and extracted from various angles, and has good fast charge and discharge performance, especially excellent low-temperature charge and discharge performance. However, due to the high specific surface area of hard carbon and the porous structure of the material itself, the electronic conductivity of the material is poor (one order of magnitude lower than that of graphite), reducing the power performance of the material.

[0003] Currently, there are many measures to improve the power performance of hard carbon, but all of them have various defects to varying degrees. For example, some measures can improve the power performance of hard carbon, but the first efficiency is relatively low, while some measures not only have a limited improvement in the power performance of hard carbon, but also reduce the cycle performance and high-temperature storage performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-power hard carbon composite material, a preparation method thereof, and a battery, aiming to solve the technical problems of low electronic conductivity, poor power performance, low first efficiency, and poor cycle performance and high-temperature storage performance of hard carbon.

[0005] To achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0006] In the first aspect, the present invention provides a preparation method of a high-power hard carbon composite material, including the following steps:

[0007] Step S1, preparing a modified metal powder;

[0008] Step S2, mixing the modified metal powder with a saccharide compound, a cross-linking agent, and a magnetic oxide for a reaction, filtering, drying, and carbonizing to obtain a hard carbon material;

[0009] Step S3, mixing the hard carbon material with asphalt, an organic solvent, and an organic sodium salt for a reaction, filtering, drying, and carbonizing to obtain the high-power hard carbon composite material.

[0010] As an implementation manner, the mass ratio of the modified metal powder, the saccharide compound, the cross-linking agent, and the magnetic oxide is (1 - 5):100:(1 - 5):(0.5 - 2).

[0011] As an implementation manner, the magnetic oxide is at least one of iron tetroxide, cobalt tetroxide, and nickel tetroxide; and / or,

[0012] The crosslinking agent is at least one of formaldehyde, acetaldehyde, and glutaraldehyde.

[0013] Furthermore, the saccharide compound is at least one of glucose, sucrose, starch, and cellulose.

[0014] Furthermore, in the step S2, the temperature of the blending reaction is 150°C to 250°C, and the time is 1 h to 6 h.

[0015] Furthermore, in the step S2, the temperature of carbonization is 1200°C to 1500°C, and the time is 1 h to 6 h.

[0016] In the present invention, the orientation of the carbon material is changed by adding magnetic oxides to improve the ion insertion channels of the material, thereby improving the power performance; in particular, when the mass ratio of the modified metal powder, saccharide compound, crosslinking agent, and magnetic oxide is (1 to 5):100:(1 to 5):(0.5 to 2), better power performance and storage performance are obtained. When the content of the magnetic oxide is too high, the storage performance and cycling performance will be reduced, and when the content is too low, it will be limited to improving the power performance of the material.

[0017] As an implementation manner, the mass ratio of the asphalt, the organic solvent, the organic sodium salt, and the hard carbon material is (10 to 30):(500 to 1000):(1 to 5):100.

[0018] As an implementation manner, the organic sodium salt is at least one of sodium tetrafluoroborate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethanesulfonate, sodium bis(oxalato)borate, sodium difluoro(oxalato)borate, sodium difluorobis(oxalato)phosphate, and sodium tetrafluoro(oxalato)phosphate.

[0019] Furthermore, the organic solution is at least one of toluene, xylene, carbon tetrachloride, and cyclohexane.

[0020] Furthermore, in the step S3, the temperature of the blending reaction is 100°C to 200°C, and the time is 1 h to 6 h.

[0021] Furthermore, in the step S3, the temperature is raised to 700°C to 1200°C at a rate of 1°C / min to 10°C / min, and carbonized for 1 h to 6 h.

[0022] In the present invention, by coating the outer layer of the hard carbon composite material with sodium-doped amorphous carbon, the irreversible capacity of the material is reduced, and the first efficiency, cycle performance, and high-temperature storage performance of the material are improved. In particular, when the mass ratio of asphalt, organic solvent, organic sodium salt, and hard carbon material is (10-30):(500-1000):(1-5):100, better first efficiency and cycle performance are obtained. When the content of the organic sodium salt is too high, the safety performance will be reduced due to sodium precipitation during the charge and discharge process of the material. When the content is too low, it is not beneficial to improve the first efficiency of the material and is also unfavorable to the cycle performance of the battery.

[0023] As an embodiment, the prepared modified metal powder includes:

[0024] Mixing and reacting the pretreated metal powder with a silane coupling agent, active particles, and an organic solution to obtain the modified metal powder.

[0025] As an embodiment, the metal powder is at least one of silver powder, copper powder, nickel powder, cobalt powder, and iron powder; or,

[0026] The silane coupling agent is at least one of γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane; or,

[0027] The active particles are at least one of silver chloride, cobalt chloride, palladium chloride, and nickel chloride.

[0028] As an embodiment, the mass ratio of the metal powder, the silane coupling agent, the active particles, and the organic solution is 100:(1-10):(0.5-2):(500-1000).

[0029] Furthermore, the particle size range of the metal powder is 100 nm to 1000 nm.

[0030] Furthermore, the organic solvent used in the prepared modified metal powder is the same as the organic solvent used in step S3.

[0031] Furthermore, in the prepared modified metal powder, the temperature of the blending reaction is 50°C to 150°C, and the time is 30 min to 300 min.

[0032] Furthermore, in the prepared modified metal powder, the pretreatment is performed by washing the metal powder with ethanol and ultrasonic cleaning.

[0033] By using modified metal, the present invention improves the dispersion performance of the material and its compatibility with the electrolyte compared with unmodified metal. At the same time, substances such as coupling agents are coated on the modified metal to reduce the swelling performance. By doping metal powder into the hard carbon core, the electronic conductivity and strength of the material are improved. Especially when the mass ratio of the metal powder, silane coupling agent, active particles, and organic solution is 100:(1-10):(0.5-2):(500-1000), better power performance effects can be obtained. When the content of the metal powder is too high, the storage performance will be reduced, and when the content is too low, the improvement of the power performance of the material will be limited.

[0034] In a second aspect, the present invention provides a high-power hard carbon composite material, which is prepared by using the preparation method of the above-mentioned high-power hard carbon composite material. The high-power hard carbon composite material presents a core-shell structure, with a hard carbon doped with metal powder as the inner core and a sodium-doped soft carbon material as the outer shell.

[0035] In a third aspect, the present invention provides a battery, including a negative electrode sheet, and the negative electrode sheet includes the above-mentioned high-power hard carbon composite material.

[0036] Compared with the prior art, the beneficial effects of the high-power hard carbon composite material, its preparation method, and the battery provided by the present invention are as follows:

[0037] (1) By doping metal powder into the hard carbon core, the electronic conductivity and strength of the material are improved, and by using modified metal, the dispersion performance of the material and its compatibility with the electrolyte are improved compared with unmodified metal. At the same time, substances such as coupling agents are coated on the modified metal to reduce the swelling performance;

[0038] (2) By adding magnetic oxides, the orientation of the carbon material is changed, the ion insertion channels of the material are improved, and thus the power performance is improved;

[0039] (3) By coating sodium-doped amorphous carbon on the outer layer of the hard carbon composite material, the irreversible capacity of the material is reduced, and the first efficiency, cycle performance, and high-temperature storage performance of the material are improved. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Among them:

[0042] Figure 1 It is the SEM diagram of the high-power hard carbon composite material prepared in Example 1 of the present invention. Detailed implementation manners

[0043] Next, in combination with the accompanying drawings and specific implementation manners, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments with each other.

[0044] The first aspect of the embodiments of the present application provides a preparation method of a high-power hard carbon composite material, including the following steps:

[0045] Step S1, preparing a modified metal powder;

[0046] Step S2, mixing and reacting the modified metal powder with a saccharide compound, a crosslinking agent, and a magnetic oxide, filtering, drying, and carbonizing to obtain a hard carbon material;

[0047] Step S3, mixing and reacting the hard carbon material with asphalt, an organic solvent, and an organic sodium salt, filtering, drying, and carbonizing to obtain the high-power hard carbon composite material.

[0048] The preparation method of the high-power hard carbon composite material provided by the first aspect of the embodiments of the present application improves the electronic conductivity and strength of the material by doping a metal powder in the hard carbon core, and improves the dispersion performance and compatibility with the electrolyte of the material by using a modified metal as compared with a non-modified metal. At the same time, substances such as a coupling agent are coated on the modified metal to reduce the expansion performance; the orientation of the carbon material is changed by adding a magnetic oxide to improve the ion insertion channels of the material, thereby improving the power performance; the irreversible capacity of the material is reduced by coating sodium-doped amorphous carbon on the outer layer of the hard carbon composite material, and the first efficiency, cycle performance, and high-temperature storage performance of the material are improved. The high-power hard carbon composite material obtained by the embodiments of the present application is a sodium-doped soft carbon-coated metal-doped hard carbon composite material.

[0049] The second aspect of the embodiments of the present application provides a high-power hard carbon composite material. The high-power hard carbon composite material is prepared by using the above-mentioned preparation method of the high-power hard carbon composite material. The high-power hard carbon composite material presents a core-shell structure, with a hard carbon doped with a metal powder as the inner core and a sodium-doped soft carbon material as the outer shell. The high-power hard carbon composite material provided by the second aspect of the present application greatly improves the power performance, the first efficiency, cycle performance, and high-temperature storage performance of the material.

[0050] The third aspect of the embodiments of the present application provides a battery, including a negative electrode sheet, and the negative electrode sheet includes the above-mentioned high-power hard carbon composite material. By using the above-mentioned high-power hard carbon composite material, it has good fast charging performance.

[0051] Specific embodiments are provided below for illustration.

[0052] Example 1

[0053] This embodiment provides a high-power hard carbon composite material, and its preparation method includes the following steps:

[0054] Step S1:

[0055] Prepare modified metal powder: Wash silver powder with a particle size of 500 nm with 75% ethanol and ultrasonic clean it. Then, take 100 g of silver powder and add it to an organic solution of 5 g of γ-aminopropylmethyldiethoxysilane, 1 g of silver chloride, and 800 g of xylene, and react at a temperature of 100 °C for 90 min to obtain modified silver powder;

[0056] Step S2:

[0057] Add 3 g of modified silver powder to 100 g of glucose compound, add 3 g of formaldehyde cross-linking agent and 1 g of iron tetroxide, disperse evenly, then transfer to a high-pressure reactor, react at a temperature of 200 °C for 3 h, filter, vacuum dry at 80 °C for 24 h, and then heat up to 1250 °C for carbonization for 3 h to obtain a hard carbon material;

[0058] Step S3:

[0059] Add 20 g of asphalt to 800 g of xylene organic solvent and disperse evenly. Then add 3 g of sodium tetrafluoroborate and disperse evenly, and then add 100 g of hard carbon material for ultrasonic dispersion evenly. React at a temperature of 150 °C for 3 h, filter, vacuum dry at 80 °C for 24 h, and then transfer to a tube furnace. Under an argon inert atmosphere, heat up to 900 °C at a heating rate of 5 °C / min for carbonization for 3 h to obtain a high-power hard carbon composite material. The SEM image is as Figure 1 shown.

[0060] Example 2

[0061] This embodiment provides a high-power hard carbon composite material, and its preparation method includes the following steps:

[0062] Step S1:

[0063] Prepare modified metal powder:

[0064] Wash 100 g of metal copper powder with a particle size of 100 nm with 75% ethanol and ultrasonic clean it. Then add it to an organic solution of 1 g of γ-aminopropyltrimethoxysilane, 0.5 g of cobalt chloride, and 500 g of carbon tetrachloride, and react at a temperature of 50 °C for 300 min to obtain modified copper powder;

[0065] Step S2:

[0066] Add 1 g of modified copper powder to 100 g of sucrose compound, add 1 g of acetaldehyde crosslinking agent and 0.5 g of cobalt tetroxide, disperse them evenly, then transfer to a high-pressure reactor, react at 150 °C for 6 h, filter, vacuum dry at 80 °C for 24 h, and then heat up to 1200 °C for carbonization for 6 h to obtain a hard carbon material;

[0067] Step S3:

[0068] Add 10 g of asphalt to 500 g of carbon tetrachloride organic solvent and disperse evenly. Then add 1 g of sodium bis(fluorosulfonyl)imide and disperse evenly. Add 100 g of hard carbon material and disperse evenly by ultrasonic treatment. React at 100 °C for 6 h, filter, vacuum dry at 80 °C for 24 h, and then transfer to a tube furnace. Under an argon inert atmosphere, heat up to 700 °C at a heating rate of 1 °C / min for carbonization for 6 h to obtain a high-power hard carbon composite material.

[0069] Example 3

[0070] This example provides a high-power hard carbon composite material, and its preparation method includes the following steps:

[0071] Step S1:

[0072] Prepare modified metal powder: Wash 100 g of metal iron powder with a particle size of 1000 nm with 75% ethanol, clean it by ultrasonic treatment, then add 10 g of γ-aminopropyltriethoxysilane, 2 g of nickel chloride to 1000 g of cyclohexane organic solution, and react at 150 °C for 30 min to obtain modified iron powder;

[0073] Step S2:

[0074] Add 5 g of modified iron powder to 100 g of starch compound, add 5 g of glutaraldehyde crosslinking agent and 2 g of nickel tetroxide, disperse evenly, then transfer to a high-pressure reactor, react at 250 °C for 1 h, filter, vacuum dry at 80 °C for 24 h, and then heat up to 1500 °C for carbonization for 1 h to obtain a hard carbon material;

[0075] Step S3:

[0076] Add 30 g of asphalt to 1000 g of cyclohexane organic solvent and disperse evenly. Then add 5 g of sodium trifluoromethanesulfonate and disperse evenly. Add 100 g of hard carbon material and disperse evenly by ultrasonic treatment. React at 200 °C for 1 h, filter, vacuum dry at 80 °C for 24 h, and then transfer to a tube furnace. Under an argon inert atmosphere, heat up to 1200 °C at a heating rate of 10 °C / min for carbonization for 1 h to obtain a high-power hard carbon composite material.

[0077] Comparative Example 1:

[0078] This comparative example provides a hard carbon composite material. The specific implementation is different from that of Example 1 in that silver powder is used to replace the modified silver powder, and the others are the same as those in Example 1.

[0079] Comparative Example 2:

[0080] This comparative example provides a hard carbon composite material. The specific implementation is different from that of Example 1 in that in step S2, formaldehyde crosslinking agent and iron tetroxide are not added, and the others are the same as those in Example 1.

[0081] Comparative Example 3:

[0082] This comparative example provides a hard carbon composite material. The specific implementation is different from that of Example 1 in that in step S3, sodium tetrafluoroborate is not added, and the others are the same as those in Example 1.

[0083] Comparative Example 4:

[0084] This comparative example provides a hard carbon composite material. The specific implementation is different from that of Example 1 in that in step S2, 10 g of formaldehyde crosslinking agent and 4 g of iron tetroxide are added, and the others are the same as those in Example 1.

[0085] Comparative Example 5:

[0086] This comparative example provides a hard carbon composite material. The specific implementation is different from that of Example 1 in that in step S3, 12 g of sodium tetrafluoroborate is added, and the others are the same as those in Example 1.

[0087] Performance testing of the materials prepared in the above examples and comparative examples:

[0088] (1) SEM testing

[0089] SEM testing was carried out on the high-power hard carbon composite material prepared in Example 1, and the results are as Figure 1 shown. It can be seen from the figure that the hard carbon composite material prepared in Example 1 presents a spherical-like structure with uniform size distribution, and the particle size is between 5 μm and 10 μm.

[0090] (2) Physical and chemical properties and coin cell testing

[0091] Particle size, tapped density, specific surface area, porosity and specific capacity testing were carried out on the hard carbon composite materials prepared in Examples 1 to 3 and Comparative Examples 1 to 5. Testing method: GBT-24533-2019 "Graphite Anode Materials for Lithium-Ion Batteries". The porosity was measured using Mastersizer 3000 and NOVA 2000e, and the pore size was measured using NOVA touch and a pore size analyzer.

[0092] The hard carbon composite materials prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were assembled into button cells A1, A2, A3, B1, B2, B3, B4, and B5 respectively; the preparation method was as follows: a binder, a conductive agent, and a solvent were added to the negative electrode material, stirred to make a slurry, coated on a copper foil, and obtained through drying and rolling. The binder used was LA132 binder, the conductive agent was SP, the negative electrode materials were the hard carbon composite materials prepared in Examples 1 to 3 and Comparative Examples 1 to 5 respectively, the solvent was secondary distilled water, and the ratio was: negative electrode material: SP: LA132: secondary distilled water = 94 g: 2 g: 4 g: 220 mL, and a negative electrode plate was prepared; the electrolyte was NaPF6 / EC + DEC (volume ratio 1:1, concentration 1.1 mol / L), a sodium metal sheet was used as the counter electrode, and the separator was a polyethylene PE, polypropylene PP, or polyethylene-propylene PEP composite membrane. The simulation battery was assembled in a glove box filled with argon, and the electrochemical performance was tested on a Wuhan Blue Electric CT2001A battery tester. The charge-discharge voltage range was 0.00 V to 2.0 V, and the charge-discharge rate was 0.1C. At the same time, the rate (2C / 0.1C) and cycle performance (0.2C / 0.2C, 200 times) of the button cells were tested, and the test results are shown in Table 1:

[0093] Table 1

[0094]

[0095] As can be seen from Table 1, compared with each comparative example, the initial discharge specific capacity, initial efficiency, rate performance, and cycle performance of the high-power hard carbon composite materials (i.e., sodium-doped soft carbon-coated metal-doped hard carbon composite materials) prepared in Examples 1 to 3 were significantly improved. In the examples of the present invention, by using a modified metal, compared with the unmodified metal, the dispersion performance of the material and the compatibility with the electrolyte were improved. At the same time, substances such as coupling agents were coated in the modified metal to reduce the swelling performance; by doping metal powder in the hard carbon core, the electronic conductivity of the material was improved and the rate was improved; by magnetic oxides, the orientation of the carbon material was changed, and the ion insertion channels of the material were improved, thereby improving the power performance; at the same time, by coating sodium-doped amorphous carbon on the outer layer, the irreversible capacity of the material was reduced, thereby improving the initial efficiency and cycle performance of the material.

[0096] (3) Soft-pack battery test:

[0097] The hard carbon composite materials prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were used as the negative electrode, and a negative electrode plate was prepared through slurrying and coating. Using a layered oxide (NaFe 1 / 3 Mn 1 / 3 Ni 1 / 3Using O2 as the positive electrode, NaPF6 (with the solvent being EC + DEC, volume ratio 1:1, concentration 1.3 mol / L) as the electrolyte, and celegard 2400 as the separator, a 2 Ah soft-pack battery was prepared.

[0098] High-temperature storage performance test:

[0099] Test method: The test conditions were as follows: At 60 °C, the capacity of the battery in a fully charged state was X1. After placing it at 60 °C for 30 days, the capacity of the battery was tested again as X2, and the charge retention was calculated as X2 / X1 * 100%; then the battery was fully charged to a fully charged state (100% SOC), the capacity of the battery was tested as X3, and the recovery capacity was calculated as X3 / X1 * 100%.

[0100] Cycling performance: Temperature 25 °C, 1C / 1C, 500 cycles.

[0101] The results are shown in Table 2:

[0102] Table 2

[0103]

[0104]

[0105] As can be seen from Table 2, the high-temperature storage performance of the materials in each example is better than that of the comparative example. The outer layer of the hard carbon composite material in the examples of the present invention is doped with sodium-doped amorphous carbon, which reduces the irreversible loss during charge and discharge of the material and improves the high-temperature storage performance; at the same time, the magnetic oxide doped in the inner core of the material changes the orientation arrangement of carbon, improves the insertion and extraction of sodium ions during charge and discharge, reduces expansion, and thus improves the cycling performance.

[0106] The above-mentioned implementation manners are only the preferred implementation manners of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention belong to the scope required to be protected by the present invention.

Claims

1. A preparation method of a high-power hard carbon composite material, characterized in that, It includes the following steps: Step S1: The pre-treated metal powder is blended and reacted with a silane coupling agent, active particles, and an organic solution to obtain a modified metal powder. Among them, the metal powder is at least one of silver powder, copper powder, nickel powder, cobalt powder, and iron powder, and the active particles are at least one of silver chloride, cobalt chloride, palladium chloride, and nickel chloride; Step S2: The modified metal powder is blended and reacted with a saccharide compound, a cross-linking agent, and a magnetic oxide, filtered, dried, and carbonized to obtain a hard carbon material; Step S3: The hard carbon material is blended and reacted with pitch, an organic solvent, and an organic sodium salt, filtered, dried, and carbonized to obtain the high-power hard carbon composite material.

2. The preparation method of the high-power hard carbon composite material according to claim 1, characterized in that, The mass ratio of the modified metal powder, the saccharide compound, the cross-linking agent, and the magnetic oxide is (1-5):100:(1-5):(0.5-2).

3. The preparation method of the high-power hard carbon composite material according to claim 1, characterized in that, The magnetic oxide is at least one of iron tetroxide, cobalt tetroxide, and nickel tetroxide; and / or, The cross-linking agent is at least one of formaldehyde, acetaldehyde, and glutaraldehyde.

4. The preparation method of the high-power hard carbon composite material according to claim 1, characterized in that, The mass ratio of the pitch, the organic solvent, the organic sodium salt, and the hard carbon material is (10-30):(500-1000):(1-5):

100.

5. The preparation method of the high-power hard carbon composite material according to claim 1, characterized in that The organic sodium salt is at least one of sodium tetrafluoroborate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethanesulfonate, sodium bis(oxalato)borate, sodium difluoro(oxalato)borate, sodium difluorobis(oxalato)phosphate, and sodium tetrafluoro(oxalato)phosphate.

6. The preparation method of the high-power hard carbon composite material according to any one of claims 1 to 5, characterized in that, The silane coupling agent is at least one of γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

7. The preparation method of the high-power hard carbon composite material according to any one of claims 1 to 5, characterized in that, The mass ratio of the metal powder, the silane coupling agent, the active particles, and the organic solution is 100:(1-10):(0.5-2):(500-1000).

8. A high-power hard carbon composite material, characterized in that, The high-power hard carbon composite material is prepared by using the preparation method of the high-power hard carbon composite material according to any one of claims 1 to 7. The high-power hard carbon composite material presents a core-shell structure, with the inner core being hard carbon doped with metal powder and the outer shell being sodium-doped soft carbon material.

9. A battery, characterized in that, It includes a negative electrode sheet, and the negative electrode sheet includes the high-power hard carbon composite material according to claim 8.

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