An empowerment-driven carbon material, and a preparation method and application thereof

Abstract

The application belongs to the technical field of secondary battery negative electrode materials, and provides a carbon material driven by energy endowment as well as a preparation method and application thereof. The method comprises the following steps: sequentially performing ball milling, pressing and carbonization treatment on a carbon precursor to obtain a carbon material. Firstly, by controlling the type of the precursor, parameters in the high-energy ball milling process such as rotating speed, time, medium and ball-to-material ratio, a powder-shaped building block with a large number of edge high-activity sites is obtained; then by controlling the pressing time and pressure, the mutual contact between the edge active sites of the building block is strengthened; finally by controlling the carbonization process, a carbon material with excellent performance is obtained. By reasonably setting various process conditions, the size, stacking, edge defects, distribution state and closed pore structure of the graphite-like microcrystals in the microstructure of the material can be effectively controlled. According to the structural parameters, the obtained material is suitable for the negative electrode of sodium ion batteries and potassium ion batteries, and has excellent electrochemical performance, especially low-potential performance.

Description

Technical Field

[0001] This invention relates to the field of secondary battery anode material technology, and in particular to an energy-driven carbon material, its preparation method, and its application. Background Technology

[0002] With the continuous development of electric vehicles and large-scale energy storage systems, the development of low-cost, reliable electrochemical energy storage systems is urgently needed. The operating voltage of a battery depends on the voltage difference between the positive and negative electrodes. From the perspective of the negative electrode, improving the operating voltage and even the energy density of the entire battery device requires the development of carbon anode materials with excellent low-potential performance.

[0003] Activated carbon is abundant and inexpensive, possesses a large specific surface area, well-developed pores, and good electrical conductivity. However, its loose, porous, and disordered carbon structure leads to ion storage via adsorption, resulting in very small low-potential capacity and no plateau. Furthermore, the significant irreversible reaction reduces the initial coulombic efficiency of the battery. Researchers both domestically and internationally have conducted extensive studies to adjust the structure of activated carbon, such as activation, template methods, and self-assembly. While these methods have achieved some success, they have not significantly improved low-potential performance when used as anode materials for potassium-ion batteries, and the processes are complex and have low success rates. In contrast, anthracite is abundant and initially possesses a graphite-like microcrystalline structure. However, the carbon materials obtained from direct carbonization of anthracite have many stacked microcrystalline layers, making it difficult to form a closed-pore structure, which is unfavorable for low-potential sodium storage. Activation can introduce porous structures, but most are open-pore structures, leading to sloping sodium storage. In addition, current processes are complex and costly, making them difficult to use practically.

[0004] Therefore, it is of great significance to find a simple and controllable method for preparing sodium and potassium ion battery anode materials to improve the overall performance of sodium and potassium ion batteries, especially their low-potential performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide an energy-driven carbon material, its preparation method and application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing an energy-driven carbon material, comprising the following steps:

[0008] The carbon precursor is sequentially subjected to ball milling, pressing and carbonization to obtain the energy-driven carbon material.

[0009] Preferably, the carbon precursor is activated carbon or anthracite.

[0010] Preferably, the specific surface area of ​​the activated carbon is 500–4500 m². 2 / g;

[0011] The anthracite coal has a carbon content of 85-99% and a volatile matter content of ≤10%.

[0012] Preferably, the atmosphere in the ball mill is an inert atmosphere;

[0013] The mass ratio of grinding balls to carbon precursor used in ball milling is 2 to 200:1.

[0014] Preferably, the ball mill rotates at a speed of 500–1200 r / min for 2–100 h.

[0015] Preferably, the pressing pressure is 1-20 MPa and the holding time is 3-300 min.

[0016] Preferably, the atmosphere for the carbonization treatment is an inert atmosphere;

[0017] The carbonization treatment is carried out at a temperature of 300–2000℃ and for a holding time of 1–36 hours.

[0018] The present invention also provides an energy-driven carbon material obtained by the preparation method described above.

[0019] The present invention also provides the application of the aforementioned energy-driven carbon material in sodium and potassium-ion battery anode materials.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention provides a method for preparing carbon materials, comprising the following steps: sequentially subjecting a carbon precursor to high-speed ball milling for energy activation, pressing to promote coalescence, and carbonization to obtain an activated carbon material. This invention first obtains powdered building blocks with numerous highly active edge sites by controlling the type of precursor and parameters during the high-energy ball milling process, such as rotation speed, time, medium, and ball-to-material ratio; then, by controlling the pressing time and pressure, it enhances the contact between the active edge sites of the building blocks; finally, by controlling the carbonization process, it obtains a carbon material with excellent performance. By rationally setting each process condition, the size, stacking, edge defects, distribution state, and closed-cell structure of the material's microstructure, resembling graphite crystals, can be effectively controlled.

[0022] 2. In this invention, the carbon precursor is activated carbon or anthracite. Activated carbon is loose, porous, and highly disordered, lacking the ability to store potassium at low potentials. After high-energy ball milling treatment according to this invention, activated carbon can be used as a precursor to form a carbon material with large interlayer spacing and short-range order. When used as a negative electrode material for potassium-ion batteries, K... +Embedded microcrystalline carbon layers with large interlayer spacing exhibit excellent low-potential performance and simultaneously improve rate performance and cycle stability. Anthracite already possesses a preliminary graphite-like microcrystalline structure, but its relatively regular stacking and limited closed-cell structure are unfavorable for sodium storage. After high-energy ball milling treatment according to this invention, the microcrystalline structure can be distorted, and the number of stacked layers can be reduced, thereby forming closed cells and increasing sodium storage capacity. + It uses a closed-cell filling method for low-pressure sodium storage, providing an excellent low-potential sodium storage platform.

[0023] 3. The ball milling in this invention is a high-energy ball milling process, which is not merely about material collisions and simple material breakage. The high-energy ball milling in this invention can energize the material; the powerful impact and shear forces generated can break carbon-carbon bonds. The mechanical pyrolysis of the carbon skeleton produces highly active carbon free radicals, creating building blocks with numerous active sites, facilitating subsequent assembly. Furthermore, this invention performs ball milling under an inert atmosphere, preventing the introduction of oxygen, protecting the active sites formed during the high-energy ball milling process, preventing carbon active sites from deactivating upon contact with oxygen, and preventing broken carbon-carbon bonds from transforming into oxygen-containing functional groups. Excessive oxygen-containing functional groups lead to an increase in the material's specific surface area, reducing low-potential performance and coulombic efficiency.

[0024] 4. The present invention presses the ball-milled material into a block solid after ball milling, which can tightly connect the material with abundant active sites on the surface, improve the mutual contact between active sites at the edge of the building blocks, help stabilize the formation of carbon structure during carbonization, and improve the cycle stability of the battery.

[0025] 5. The raw materials for this invention are abundant, the preparation process is simple, and it offers strong design flexibility. Based on their structural parameters, the resulting materials can be applied to the anodes of both sodium-ion and potassium-ion batteries. When the energy-driven carbon material (with activated carbon as the carbon precursor) described in this invention is used as a carbon anode material for potassium-ion batteries, it exhibits excellent low-potential performance and synergistically improves rate performance and cycle stability. When the energy-driven carbon material (with anthracite as the carbon precursor) described in this invention is used as a carbon anode material for sodium-ion batteries, it has a long low-potential plateau and synergistically improves rate performance and cycle stability. The energy-driven carbon material prepared by this invention plays a crucial role in improving battery energy density. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the specific preparation process of the energy-driven carbon material in this invention.

[0027] Figure 2 This is a transmission electron microscope (TEM) characterization image of the energy-driven carbon material in Example 1;

[0028] Figure 3The charge-discharge curves of the potassium-ion battery in Example 1 at a current density of 50 mA / g (Specific Capacity, Potential, Voltage);

[0029] Figure 4 The graph shows the cycle performance of the potassium-ion battery in Example 1 at a current density of 50 mA / g (Cyclenumber—number of cycles, Specific Capacity—specific capacity).

[0030] Figure 5 The charge-discharge curves of the potassium-ion battery in Example 3 at a current density of 50 mA / g (Specific Capacity, Potential, Voltage);

[0031] Figure 6 The cyclic volt-ampere curve (Voltage—voltage, Current—current) of the potassium-ion battery in Example 3;

[0032] Figure 7 This is a scanning electron microscope (SEM) characterization image of the energy-driven carbon material in Example 7;

[0033] Figure 8 The charge-discharge curves of the sodium-ion battery in Example 7 at a current density of 20 mA / g (Specific Capacity, Potential, Voltage);

[0034] Figure 9 The diagram shows the cycle performance of the sodium-ion battery in Example 7 at a current density of 20 mA / g (Cyclenumber—number of cycles, Specific Capacity—specific capacity).

[0035] Figure 10 The cyclic voltammogram (Cycle number—number of cycles, Specific Capacity—specific capacity) of the potassium-ion battery in Comparative Example 1 is shown.

[0036] Figure 11 Transmission electron microscopy (TEM) characterization of the energy-driven carbon material in Comparative Example 2;

[0037] Figure 12 The charge-discharge curves of the potassium-ion battery in Comparative Example 2 at a current density of 50 mA / g (Specific Capacity, Potential, Voltage);

[0038] Figure 13The charge-discharge curves of the potassium-ion battery in Comparative Example 4 at a current density of 50 mA / g (Specific Capacity, Potential, Voltage).

[0039] Figure 14 The charge-discharge curves of the sodium-ion battery in Comparative Example 6 at a current density of 20 mA / g (Specific Capacity, Potential Voltage);

[0040] Figure 15 The charge-discharge curves of the sodium-ion battery in Comparative Example 8 at a current density of 20 mA / g are shown (Specific Capacity, Potential Voltage). Detailed Implementation

[0041] This invention provides a method for preparing an energy-driven carbon material, comprising the following steps:

[0042] The carbon precursor is sequentially subjected to ball milling, pressing and carbonization to obtain the energy-driven carbon material.

[0043] In this invention, the carbon precursor is preferably activated carbon or anthracite.

[0044] In this invention, activated carbon is loose, porous, and highly disordered, lacking the ability to store potassium at low potentials. However, after high-energy ball milling, activated carbon can be used as a precursor to form a carbon material with large interlayer spacing and short-range order. When used as a negative electrode material for potassium-ion batteries, K... + Embedded microcrystalline carbon layers with large interlayer spacing exhibit excellent low-potential performance and simultaneously improve rate performance and cycle stability. Anthracite already possesses a preliminary graphite-like microcrystalline structure, but its relatively regular stacking and limited closed-cell structure are unfavorable for sodium storage. After high-energy ball milling treatment according to this invention, the microcrystalline structure can be distorted, and the number of stacked layers can be reduced, thereby forming closed cells and increasing sodium storage capacity. + It uses a closed-cell filling method for low-pressure sodium storage, providing an excellent low-potential sodium storage platform.

[0045] In this invention, the specific surface area of ​​the activated carbon is preferably 500–4500 m². 2 / g, further preferably 1349~3000m 2 / g, more preferably 1860~2187m 2 / g.

[0046] In this invention, the carbon content of the anthracite is preferably 85-99%, more preferably 88-96%, and even more preferably 90-93%; the volatile matter is preferably ≤10%, more preferably ≤9%, and even more preferably ≤8%.

[0047] In this invention, the ball milling atmosphere is preferably an inert atmosphere; during the ball milling process, the inert atmosphere is preferably a mixture of argon and hydrogen, a mixture of nitrogen and hydrogen, argon, or nitrogen; the ball milling in the inert atmosphere of this invention prevents the introduction of oxygen, which can protect the active sites formed during high-energy ball milling, prevent carbon active sites from being deactivated by contact with oxygen, and prevent broken carbon-carbon bonds from transforming into oxygen-containing functional groups, because excessive oxygen-containing functional groups will lead to an increase in the specific surface area of ​​the material, reducing low potential performance and coulombic efficiency.

[0048] In this invention, the mass ratio of the grinding balls to the carbon precursor used in the ball mill is preferably 2 to 200:1, more preferably 10 to 180:1, and even more preferably 50 to 150:1.

[0049] In this invention, the grinding balls used in the ball mill preferably include zirconia grinding balls a and zirconia grinding balls b. The particle size of the zirconia grinding balls a is preferably 5-7 mm, more preferably 5.5-6.5 mm, and more preferably 6-6.2 mm. The particle size of the zirconia grinding balls b is preferably 11-13 mm, more preferably 11.5-12.5 mm, and more preferably 12-12.2 mm. The ratio of the number of zirconia grinding balls a to zirconia grinding balls b is preferably 8-24:4-12, more preferably 10-20:5-10, and more preferably 12-16:6-8.

[0050] In this invention, the rotational speed of the ball mill is preferably 500-1200 r / min, more preferably 600-1000 r / min, and even more preferably 700-950 r / min; the time is preferably 2-100 h, more preferably 8-80 h, and even more preferably 36-48 h.

[0051] In this invention, the ball milling is a high-energy ball milling, which is not just about making materials collide with each other and simply breaking them. High-energy ball milling can energize materials, and the powerful impact and shear forces generated can break carbon-carbon bonds. The mechanical pyrolysis of the carbon skeleton will generate highly active carbon free radicals, creating building blocks with a large number of active sites, which will facilitate the next step of assembly.

[0052] In this invention, the pressing pressure is preferably 1-20 MPa, more preferably 3-18 MPa, and even more preferably 5-15 MPa; the holding time is preferably 3-300 min, more preferably 10-200 min, and even more preferably 15-50 min.

[0053] In this invention, by pressing the ball-milled and energized material into a block solid, the material with abundant active sites on the surface can be tightly connected, improving the mutual contact between active sites at the edge of the building blocks, which helps to stabilize the formation of the carbon structure during the carbonization process and improve the cycle stability of the battery.

[0054] In this invention, the atmosphere for the carbonization treatment is preferably an inert atmosphere; during the carbonization process, the inert atmosphere is preferably argon, helium or nitrogen.

[0055] In this invention, the carbonization process is preferably a one-step heating carbonization process or a two-step heating carbonization process.

[0056] In this invention, the temperature of the one-step heating carbonization treatment is preferably 300-2000℃, more preferably 500-1700℃, and even more preferably 1100-1500℃; the holding time is preferably 1-36h, more preferably 5-30h, and even more preferably 10-20h; the heating rate from room temperature to the carbonization treatment temperature is preferably 0.5-20℃ / min, more preferably 5-15℃ / min, and even more preferably 8-12℃ / min.

[0057] In this invention, the intermediate temperature of the two-step heating carbonization process is preferably 300–1300°C, more preferably 500–1200°C, and even more preferably 700–1000°C; the target temperature of the two-step heating carbonization process is preferably 1500–2000°C, more preferably 1600–1900°C, and even more preferably 1700–1800°C; the holding time to reach the target temperature is preferably 1–36 h, more preferably 2–30 h, and even more preferably 3–20 h; the heating rate from room temperature to the intermediate temperature is preferably 5–20°C / min, more preferably 8–18°C / min, and even more preferably 10–15°C / min; the heating rate from the intermediate temperature to the target temperature is preferably 0.5–2°C / min, more preferably 1–1.5°C / min, and even more preferably 1.2–1.3°C / min.

[0058] In this invention, after the carbonization process is completed, the obtained sample is crushed to obtain carbon material.

[0059] A schematic diagram of the specific preparation process of the carbon material in this invention is shown below. Figure 1 As shown.

[0060] The present invention also provides an energy-driven carbon material obtained by the preparation method described above.

[0061] The present invention also provides the application of the aforementioned energy-driven carbon material in sodium and potassium-ion battery anode materials.

[0062] In this invention, when the carbon precursor is activated carbon, the resulting energy-driven carbon material is applied to potassium-ion batteries; when the carbon precursor is anthracite, the resulting energy-driven carbon material is applied to sodium-ion batteries.

[0063] In this invention, when the structure-regulated activated carbon material is used as a carbon anode material for potassium-ion batteries, the potassium storage potential can be reduced and the rate performance can be improved; when the structure-regulated anthracite material is used as a carbon anode material for sodium-ion batteries, it has a long low-potential plateau and can synergistically improve rate performance and cycle stability.

[0064] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] In an argon atmosphere, 0.5g of a substance with a specific surface area of ​​1860 m² was used. 2 / g of activated carbon was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 700r / min for 48h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment under an argon atmosphere. The intermediate temperature was set to 1200℃ and the target temperature was set to 1500℃. The holding time to reach the target temperature was 2h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0067] The activated carbon material obtained in this embodiment was characterized by transmission electron microscopy (TEM), resulting in the TEM image of the activated carbon material in this embodiment, as shown below. Figure 2 As shown; from Figure 2 As can be seen, the carbon material driven by the energy has fewer internal pores and significant carbon layer stacking, ranging from 2 to more than 10 layers. This stacking of carbon layers is conducive to the interlayer intercalation of potassium ions, enabling potassium storage at low potential.

[0068] The energy-driven carbon material prepared in this embodiment has a blocky surface with a specific surface area of ​​58 m². 2 / g, tap density is 0.71g / mL, I D / I G The value is 1.13.

[0069] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment. The steps are as follows: Energy-driven carbon material, sodium carboxymethyl cellulose, and carbon black were weighed at a mass ratio of 8:1:1, and sequentially coated, dried, stress-relieved, and dried again to obtain battery electrodes. The obtained battery electrodes were then used as the working electrode, and the potassium electrode as the counter electrode, and the potassium-ion battery was assembled in a glove box. Electrochemical performance tests were performed (using a CT2001A blue electric current testing system at room temperature of 25℃), and the charge-discharge curves of the potassium-ion battery in this embodiment at a current density of 50 mA / g were obtained, as shown below. Figure 3 As shown; the cycle performance diagram of the potassium-ion battery in this embodiment at a current density of 50 mA / g is as follows. Figure 4 As shown; from Figure 3 and 4 As can be seen, at a current density of 50 mA / g, the capacity is 350.9 mAh / g, and the capacity retention rate is 95.7% from 5 to 100 cycles. In particular, it has high capacity at low potential, with a capacity of up to 256.8 mAh / g below 1V, accounting for 73.18% of the total capacity. This indicates that the potassium-ion battery prepared in this embodiment has excellent low-potential performance as well as high rate and high cycle stability.

[0070] Example 2

[0071] In an argon atmosphere, 0.5g of a substance with a specific surface area of ​​3000m² was... 2 / g of activated carbon was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 950r / min for 36h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 15min. Then, the obtained solid was subjected to a two-step heating carbonization treatment under an argon atmosphere. The intermediate temperature was set to 1200℃ and the target temperature was set to 1500℃. The holding time to reach the target temperature was 2h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0072] The energy-driven carbon material prepared in this embodiment has a blocky surface and a specific surface area of ​​173 m². 2 / g, tap density is 0.69g / mL, I D / I G The value is 1.19.

[0073] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 1. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 348.1 mAh / g at a current density of 50 mA / g, with a capacity retention of 93.4% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 244.7 mAh / g, accounting for 70.29% of the total capacity. This indicates that the potassium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0074] Example 3

[0075] In a nitrogen atmosphere, 0.5g of a substance with a specific surface area of ​​2187 m² was used. 2 / g of activated carbon was mixed with 75g of zirconia ball milling beads (the zirconia ball milling beads consisted of 24 zirconia ball milling beads a with a particle size of 6mm and 12 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 850r / min for 48h. After ball milling, the obtained powder was pressed under a pressure of 15MPa and the holding time was set to 50min. Then, the obtained solid was subjected to a one-step heating carbonization treatment under a nitrogen atmosphere. The heating rate of the carbonization treatment was set to 5℃ / min, the temperature was set to 1100℃, and the holding time was set to 5h. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0076] The energy-driven carbon material prepared in this embodiment has a blocky surface with a specific surface area of ​​63 m². 2 / g, tap density is 0.67g / mL, I D / I G The value is 1.22.

[0077] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 1. Its electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C), and the charge-discharge curves of the potassium-ion battery in this embodiment at a current density of 50 mA / g were obtained, as shown below. Figure 5 As shown; from Figure 5 As can be seen, at a current density of 50 mA / g, the capacity is 335.9 mAh / g, and the capacity retention rate is 89.4% from 5 to 100 cycles. It exhibits particularly high capacity at low potentials, with a capacity as high as 225.8 mAh / g below 1V, accounting for 67.22% of the total capacity. This indicates that the potassium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability. Furthermore, the cyclic voltammetry curve of the potassium-ion battery in this embodiment is shown in the figure below. Figure 6 As shown; from Figure 6As can be seen, there are sharp redox peaks, and the second and third rings completely overlap, indicating that potassium ions can be reversibly inserted and extracted.

[0078] Example 4

[0079] In a nitrogen atmosphere, 0.5g of a substance with a specific surface area of ​​2187 m² was used. 2 / g of activated carbon was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 700r / min for 48h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment under a nitrogen atmosphere. The intermediate temperature was set to 1200℃ and the target temperature was set to 1500℃. The holding time to reach the target temperature was 3h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0080] The energy-driven carbon material prepared in this embodiment has a blocky surface with a specific surface area of ​​67 m². 2 / g, tap density is 0.69g / mL, I D / I G The value is 1.18.

[0081] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 1. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 310.8 mAh / g at a current density of 50 mA / g, with a capacity retention of 88.7% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity as high as 201.5 mAh / g below 1V, accounting for 64.83% of the total capacity. This indicates that the potassium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0082] Example 5

[0083] In an argon atmosphere, 0.5g of a substance with a specific surface area of ​​1349 m² was used. 2 / g of activated carbon was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 750r / min for 40h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 40min. Then, the obtained solid was subjected to a one-step heating carbonization treatment under an argon atmosphere. The heating rate of the carbonization treatment was set to 5℃ / min, the temperature was set to 1300℃, and the holding time was set to 3h. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0084] The energy-driven carbon material prepared in this embodiment has a blocky surface and a specific surface area of ​​124 m². 2 / g, tap density is 0.68g / mL, I D / I G The value is 1.19.

[0085] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 1. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 338.1 mAh / g at a current density of 50 mA / g, with a capacity retention of 89.3% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 230.9 mAh / g, accounting for 68.29% of the total capacity. This indicates that the potassium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0086] Example 6

[0087] In a nitrogen atmosphere, 0.5g of a substance with a specific surface area of ​​2584 m² was used. 2 / g of activated carbon was mixed with 50g of zirconia ball milling beads (the zirconia ball milling beads consisted of 16 zirconia ball milling beads a with a particle size of 6mm and 8 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 750r / min for 46h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment under a nitrogen atmosphere. The intermediate temperature was set to 1200℃ and the target temperature was set to 1500℃. The holding time to reach the target temperature was 3h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0088] The energy-driven carbon material prepared in this embodiment has a blocky surface and a specific surface area of ​​75 m². 2 / g, tap density is 0.70g / mL, ID / I G The value is 1.15.

[0089] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 1. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 342.7 mAh / g at a current density of 50 mA / g, with a capacity retention of 89.8% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 235.7 mAh / g, accounting for 68.77% of the total capacity. This indicates that the potassium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0090] Example 7

[0091] In an argon atmosphere, 0.5g of anthracite with a carbon content of 93% and a volatile matter content of 9% was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 700r / min for 8h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment in an argon atmosphere, with the intermediate temperature set at 1200℃ and the target temperature at 1500℃. The holding time to reach the target temperature was 2h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0092] The activated carbon material obtained in this embodiment was characterized by scanning electron microscopy (SEM), resulting in the SEM image of the activated carbon material in this embodiment, as shown below. Figure 7 As shown; from Figure 7 As can be seen, the material has a blocky structure with a particle size of about 3μm.

[0093] The energy-driven carbon material prepared in this embodiment has a specific surface area of ​​17 m². 2 / g,I D / I G The value is 0.99.

[0094] A sodium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment. The steps are as follows: The energy-driven carbon material, sodium carboxymethyl cellulose, and carbon black were weighed in a mass ratio of 8:1:1, and sequentially coated, dried, stress-relieved, and dried again to obtain battery electrodes. The obtained battery electrodes were then used as the working electrode, and the sodium electrode as the counter electrode. The sodium-ion battery was assembled in a glove box. Electrochemical performance tests were performed (using a CT2001A blue electric test system at room temperature of 25℃). The charge-discharge curves of the sodium-ion battery in this embodiment at a current density of 20 mA / g were obtained, as shown below. Figure 8 As shown; the cycle performance diagram of the sodium-ion battery in this embodiment at a current density of 20 mA / g is as follows. Figure 9 As shown; from Figures 8-9 As can be seen, at a current density of 20 mA / g, the capacity is 348.4 mAh / g, and the capacity retention rate is 98.5% from 5 to 100 cycles. It has a high capacity at low potential, with a capacity of up to 294.3 mAh / g below 1V, accounting for 84.47% of the total capacity. This indicates that the sodium-ion battery prepared in this embodiment has excellent low-potential performance as well as high rate and high cycle stability.

[0095] Example 8

[0096] In an argon atmosphere, 0.5g of anthracite with a carbon content of 90% and a volatile matter content of 8% was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 950r / min for 4h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 15min. Then, the obtained solid was subjected to a two-step heating carbonization treatment in an argon atmosphere, with the intermediate temperature set at 1200℃ and the target temperature at 1500℃. The holding time to reach the target temperature was 2h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0097] The energy-driven carbon material prepared in this embodiment has a specific surface area of ​​16 m². 2 / g,I D / I G The value is 1.12.

[0098] Sodium-ion batteries were prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 7. Electrochemical performance tests were performed (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 329.5 mAh / g at a current density of 20 mA / g, with a capacity retention of 94.3% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 267.5 mAh / g, accounting for 81.18% of the total capacity. This indicates that the sodium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0099] Example 9

[0100] In a nitrogen atmosphere, 0.5g of anthracite with a carbon content of 96% and a volatile matter content of 9% was mixed with 75g of zirconia ball milling beads (the zirconia ball milling beads consisted of 24 zirconia ball milling beads a with a particle size of 6mm and 12 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 850r / min for 8h. After ball milling, the obtained powder was pressed under a pressure of 15MPa and the holding time was set to 50min. Then, the obtained solid was subjected to a one-step heating carbonization treatment in a nitrogen atmosphere. The heating rate of the carbonization treatment was set to 5℃ / min, the temperature was set to 1100℃, and the holding time was set to 5h. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0101] The energy-driven carbon material prepared in this embodiment has a specific surface area of ​​18 m². 2 / g,I D / I G The value is 1.13.

[0102] A sodium-ion battery was prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 7. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 318.7 mAh / g at a current density of 20 mA / g, with a capacity retention of 91.8% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 263.4 mAh / g, accounting for 82.65% of the total capacity. This indicates that the sodium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0103] Example 10

[0104] In a nitrogen atmosphere, 0.5g of anthracite with a carbon content of 93% and a volatile matter content of 8% was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 700r / min for 10h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment in a nitrogen atmosphere, with the intermediate temperature set at 1200℃ and the target temperature at 1500℃. The holding time to reach the target temperature was 3h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0105] The energy-driven carbon material prepared in this embodiment has a specific surface area of ​​21 m². 2 / g,I D / I G The value is 1.12.

[0106] Sodium-ion batteries were prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 7. Electrochemical performance tests were performed (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 320.1 mAh / g at a current density of 20 mA / g, with a capacity retention of 91.3% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 270.1 mAh / g, accounting for 84.38% of the total capacity. This indicates that the sodium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0107] Example 11

[0108] In an argon atmosphere, 0.5g of anthracite with a carbon content of 90% and a volatile matter content of 8% was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 750r / min for 10h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 40min. Then, the obtained solid was subjected to a one-step heating carbonization treatment in an argon atmosphere. The heating rate of the carbonization treatment was set to 5℃ / min, the temperature was set to 1300℃, and the holding time was set to 3h. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0109] The energy-driven carbon material prepared in this embodiment has a specific surface area of ​​20 m². 2 / g,I D / I GThe value is 1.10.

[0110] Sodium-ion batteries were prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 7. Electrochemical performance tests were performed (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 311.6 mAh / g at a current density of 20 mA / g, with a capacity retention of 91.7% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity below 1V reaching 259.4 mAh / g, accounting for 83.25% of the total capacity. This indicates that the sodium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0111] Example 12

[0112] In an argon atmosphere, 0.5g of anthracite with a carbon content of 96% and a volatile matter content of 9% was mixed with 50g of zirconia ball milling beads (the zirconia ball milling beads consisted of 16 zirconia ball milling beads a with a particle size of 6mm and 8 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 750r / min for 9h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment in an argon atmosphere, with the intermediate temperature set at 1200℃ and the target temperature at 1500℃. The holding time to reach the target temperature was 3h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0113] The energy-driven carbon material prepared in this embodiment has a specific surface area of ​​19 m². 2 / g,I D / I G The value is 1.00.

[0114] Sodium-ion batteries were prepared using the energy-driven carbon material obtained in this embodiment, following the same steps as in Example 7. Electrochemical performance tests were performed (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 315.7 mAh / g at a current density of 20 mA / g, with a capacity retention of 92.4% from 5 to 100 cycles. Particularly noteworthy was the high capacity at low potentials, with a capacity as high as 268.3 mAh / g below 1V, accounting for 84.98% of the total capacity. This indicates that the sodium-ion battery prepared in this embodiment possesses excellent low-potential performance, as well as high rate capability and high cycle stability.

[0115] Comparative Example 1

[0116] In an argon atmosphere, 0.5g of a substance with a specific surface area of ​​2187 m² was used.2 / g of activated carbon was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 750r / min for 48h. After ball milling, the obtained powder was subjected to a two-step heating carbonization treatment under an argon atmosphere. The intermediate temperature was set at 1200℃, the target temperature was set at 1500℃, the holding time to reach the target temperature was 2h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0117] The energy-driven carbon material prepared in this comparative example has a blocky surface with a specific surface area of ​​182 m². 2 / g, tap density is 0.34g / mL, I D / I G The value is 1.24.

[0118] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 1. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 197.4 mAh / g at a current density of 50 mA / g, with a capacity retention of 81.3% from 5 to 100 cycles. The capacity decreased at low potentials, but reached a high of 88.7 mAh / g below 1V, accounting for 44.95% of the total capacity. This indicates that the potassium-ion battery prepared in this comparative example exhibits significantly reduced low-potential performance but good rate performance. Furthermore, the cyclic voltammetry curves of the potassium-ion battery in this comparative example are shown below. Figure 10 As shown; from Figure 10 As can be seen, there is no obvious oxidation peak, and the sharp reduction peak in the first ring corresponds to the formation of the SEI film.

[0119] Comparative Example 2

[0120] The specific surface area of ​​0.5g is 2187.48m². 2 / g of activated carbon was pressed at a pressure of 5 MPa for 10 min. The resulting solid was then subjected to a two-step heating carbonization process under an argon atmosphere. The intermediate temperature was set at 1200℃, the target temperature at 1500℃, and the holding time at the target temperature was 2 h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0121] The energy-driven carbon material obtained in this comparative example was characterized by transmission electron microscopy (TEM), and the TEM image of the energy-driven carbon material in this comparative example is shown below. Figure 11 As shown; from Figure 11 As can be seen, the material has many internal pores, and the carbon layer is curved, wrinkled, and has many defects.

[0122] The energy-driven carbon material prepared in this comparative example has a large surface bulk, with a specific surface area of ​​987 m². 2 / g, tap density is 0.32g / mL, I D / I G The value is 1.28.

[0123] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 1. Its electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C), and the charge-discharge curves of the potassium-ion battery in this comparative example at a current density of 50 mA / g were obtained, as shown below. Figure 2 As shown; from Figure 12 As can be seen, at a current density of 50 mA / g, the capacity is 108.5 mAh / g, the capacity retention rate is 80.1% from 5 to 100 cycles, and the capacity below 1V is only 39.8 mAh / g, accounting for 36.68% of the total capacity. This indicates that the potassium-ion battery prepared in this comparative example has a significantly reduced capacity and no obvious low-potential plateau.

[0124] Comparative Example 3

[0125] In a nitrogen atmosphere, 0.5 g of a substance with a specific surface area of ​​907.843 m² was used. 2 / g of activated carbon was mixed with 12.5g of zirconia ball milling beads (the zirconia ball milling beads consisted of 4 zirconia ball milling beads a with a particle size of 6mm and 2 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 400r / min for 65h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment under a nitrogen atmosphere. The intermediate temperature was set to 1200℃ and the target temperature was set to 1500℃. The holding time to reach the target temperature was 2h. The heating rate from room temperature to intermediate temperature was 5℃ / min, and the heating rate from intermediate temperature to target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0126] The energy-driven carbon material prepared in this comparative example has a large surface bulk, with a specific surface area of ​​398 m². 2 / g, tap density is 0.35g / mL, I D / I G The value is 1.31.

[0127] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 1. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 156.8 mAh / g at a current density of 50 mA / g, a capacity retention rate of 81.9% from 5 to 100 cycles, and a capacity of 67.7 mAh / g below 1V, accounting for 43.71% of the total capacity. This indicates that the potassium-ion battery prepared in this comparative example has a reduced capacity and no obvious low-potential plateau.

[0128] Comparative Example 4

[0129] In an air atmosphere, 0.5g of the sample has a specific surface area of ​​2584.762 m². 2 / g of activated carbon was mixed with 50g of zirconia ball milling beads (the zirconia ball milling beads consisted of 16 zirconia ball milling beads a with a particle size of 6mm and 8 zirconia ball milling beads b with a particle size of 12mm) and ball milled at 750r / min for 8h. After ball milling, the obtained powder was pressed under a pressure of 2MPa and the holding time was set to 15min. Then, the obtained solid was subjected to a two-step heating carbonization treatment under a nitrogen atmosphere. The intermediate temperature was set to 1200℃ and the target temperature was set to 1500℃. The holding time to reach the target temperature was 2h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0130] The energy-driven carbon material prepared in this comparative example has a bulk surface with a specific surface area of ​​1107 m². 2 / g, tap density is 0.31g / mL, I D / I G The value is 1.34.

[0131] A potassium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 1. Its electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C), and the charge-discharge curves of the potassium-ion battery in this comparative example at a current density of 50 mA / g were obtained, as shown below. Figure 13 As shown; from Figure 13 As can be seen, at a current density of 50 mA / g, the capacity is 123.7 mAh / g, the capacity retention rate is 79.3% from 5 to 100 cycles, and the capacity below 1V is 61.3 mAh / g, accounting for 49.55% of the total capacity. This indicates that the potassium-ion battery prepared in this comparative example has a significantly reduced capacity and no obvious low-potential plateau.

[0132] Comparative Example 5

[0133] In an argon atmosphere, 0.5g of anthracite with a carbon content of 96% and a volatile matter of 9% was mixed with 25g of zirconia ball milling beads (the zirconia ball milling beads consisted of 8 zirconia ball milling beads a with a particle size of 6mm and 4 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 750r / min for 8h. After ball milling, the obtained powder was subjected to a two-step heating carbonization treatment in an argon atmosphere. The intermediate temperature was set at 1200℃, the target temperature was set at 1500℃, the holding time to reach the target temperature was 2h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0134] The energy-driven carbon material prepared in this comparative example has a specific surface area of ​​30 m². 2 / g,I D / I G The value is 1.24.

[0135] A sodium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 7. Electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C). The results showed a capacity of 188.6 mAh / g at a current density of 20 mA / g, with a capacity retention of 82.3% from 5 to 100 cycles. The capacity decreased at low potentials, with a capacity of 98.6 mAh / g below 1V, accounting for 52.29% of the total capacity. This indicates that the sodium-ion battery prepared in this comparative example has high capacity and high rate capability.

[0136] Comparative Example 6

[0137] 0.5g of anthracite with a carbon content of 96% and a volatile matter content of 9% was pressed at a pressure of 5 MPa for 10 min. The resulting solid was then subjected to a two-step heating carbonization process under an argon atmosphere, with an intermediate temperature of 1200℃ and a target temperature of 1500℃. The holding time to reach the target temperature was 2 h. The heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0138] The energy-driven carbon material prepared in this comparative example has a specific surface area of ​​20 m². 2 / g,I D / I G The value is 1.15.

[0139] A sodium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 7. Its electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C), and the charge-discharge curves of the sodium-ion battery in this comparative example at a current density of 20 mA / g were obtained, as shown below. Figure 14 As shown; from Figure 14 As can be seen, at a current density of 20 mA / g, the capacity is 250.4 mAh / g, and the capacity retention rate is 81.7% from 5 to 100 cycles. The capacity decreases at low potentials, and the capacity below 1V is 87.4 mAh / g, accounting for 34.90% of the total capacity. This indicates that the sodium-ion battery prepared in this comparative example has reduced capacity and poor rate performance.

[0140] Comparative Example 7

[0141] In an argon atmosphere, 0.5g of anthracite with a carbon content of 96% and a volatile matter content of 9% was mixed with 12.5g of zirconia ball milling beads (the zirconia ball milling beads consisted of four zirconia ball milling beads a with a particle size of 6mm and two zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 400r / min for 65h. After ball milling, the obtained powder was pressed under a pressure of 5MPa and the holding time was set to 10min. Then, the obtained solid was subjected to a two-step heating carbonization treatment in an argon atmosphere, with the intermediate temperature set at 1200℃ and the target temperature at 1500℃. The holding time to reach the target temperature was 2h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0142] The energy-driven carbon material prepared in this comparative example has a specific surface area of ​​23 m². 2 / g,I D / I G The value is 1.14.

[0143] A sodium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 7. Electrochemical performance was tested (using a CT2001A blue electric test system at room temperature of 25°C). The results showed a capacity of 179.8 mAh / g at a current density of 20 mA / g, with a capacity retention of 84.9% from 5 to 100 cycles. The capacity decreased at low potentials, with a capacity of 88.8 mAh / g below 1V, accounting for 49.38% of the total capacity. This indicates that the sodium-ion battery prepared in this comparative example has reduced capacity and poor rate performance.

[0144] Comparative Example 8

[0145] In an oxygen atmosphere, 0.5g of anthracite with a carbon content of 96% and a volatile matter of 9% was mixed with 50g of zirconia ball milling beads (the zirconia ball milling beads consisted of 16 zirconia ball milling beads a with a particle size of 6mm and 8 zirconia ball milling beads b with a particle size of 12mm) and ball milled at a speed of 750r / min for 8h. After ball milling, the resulting powder was pressed under a pressure of 2MPa and the holding time was set to 15min. Then, the resulting solid was subjected to a two-step heating carbonization treatment in an argon atmosphere, with the intermediate temperature set at 1200℃ and the target temperature at 1500℃. The holding time to reach the target temperature was 2h, the heating rate from room temperature to the intermediate temperature was 5℃ / min, and the heating rate from the intermediate temperature to the target temperature was 2℃ / min. Finally, the obtained sample was pulverized to obtain the energy-driven carbon material.

[0146] The energy-driven carbon material prepared in this comparative example has a specific surface area of ​​28 m². 2 / g,I D / I G The value is 1.12.

[0147] A sodium-ion battery was prepared using the energy-driven carbon material obtained in this comparative example, following the same steps as in Example 7. Its electrochemical performance was tested (using a CT2001A blue electric current testing system at room temperature of 25°C), and the charge-discharge curves of the sodium-ion battery in this comparative example at a current density of 20 mA / g were obtained, as shown below. Figure 15 As shown; from Figure 15 As can be seen, at a current density of 20 mA / g, the capacity is 320 mAh / g, and the capacity retention rate is 80.1% from 5 to 100 cycles. The capacity decreases at low potentials, and the capacity below 1V is 55.0 mAh / g, accounting for 17.2% of the total capacity. This indicates that the sodium-ion battery prepared in this comparative example has reduced capacity and poor rate performance.

[0148] As can be seen from the above embodiments, compared with the unmilled activated carbon material, the activated carbon material of the present invention has more graphite-like microcrystalline stacked layers and a larger interlayer spacing. Through Examples 1-12 and Comparative Examples 1-8, it can be seen that only high-energy ball milling can energize the material, forming a large number of active sites on the material surface, significantly improving the material's performance; pressing the material energized by high-energy ball milling into shape can make the material with abundant active sites on the surface more tightly connected, which helps to stabilize the formation of the carbon structure during carbonization and improve the material's stability; ball milling in an inert atmosphere, compared with ball milling in air, can avoid the strong impact and shear forces during ball milling from damaging the carbon-carbon bonds, introducing excessive oxygen, and thus forming oxygen-containing functional groups inside the material, thereby reducing the coulombic efficiency of the battery.

[0149] This invention provides a method for preparing carbon materials, comprising the following steps: under an inert atmosphere, a carbon precursor is sequentially subjected to high-speed ball milling for energy enhancement, pressing to promote coalescence, and carbonization to obtain the carbon material. This invention first obtains powdered building blocks with numerous highly active edge sites by controlling the type of precursor and parameters during the high-energy ball milling process, such as rotation speed, time, medium, and ball-to-material ratio; then, by controlling the pressing time and pressure, the contact between the active edge sites of the building blocks is enhanced; finally, by controlling the carbonization process, a carbon material with excellent performance is obtained. By rationally setting each process condition, the size, stacking, edge defects, distribution state, and closed-cell structure of the material's microstructure, resembling graphite crystals, can be effectively controlled.

[0150] The raw materials used in this invention are abundant, the preparation process is simple, and it offers strong design flexibility. When the activated carbon material described in this invention is used as a carbon anode material for potassium-ion batteries, it exhibits excellent low-potential performance and synergistically improves rate performance and cycle stability. When the anthracite material described in this invention is used as a carbon anode material for sodium-ion batteries, it has a long low-potential plateau and synergistically improves rate performance and cycle stability. The energy-driven carbon material prepared by this invention plays a crucial role in improving battery energy density.

[0151] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an energy-driven carbon material, characterized in that, Includes the following steps: The carbon precursor is sequentially subjected to ball milling, pressing and carbonization to obtain the energy-driven carbon material. The carbon precursor is activated carbon; The atmosphere in the ball mill is an inert atmosphere; The mass ratio of grinding balls to carbon precursor used in ball milling is 2 to 200:1; The ball mill operates at a speed of 500–1200 r / min for 2–100 h. The pressing pressure is 1-20 MPa, and the holding time is 3-300 min.

2. The preparation method according to claim 1, characterized in that, The specific surface area of ​​the activated carbon is 500–4500 m². 2 / g.

3. The preparation method according to claim 2, characterized in that, The atmosphere for the carbonization process is an inert atmosphere; The carbonization process is carried out at a temperature of 300–2000℃ and for a holding time of 1–36 hours.

4. The energy-driven carbon material obtained by the preparation method according to any one of claims 1 to 3.

5. The application of the energy-driven carbon material as described in claim 4 in the anode material of sodium and potassium ion batteries.

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