A high-capacity resin-based hard carbon material, and a preparation method and application thereof

Abstract

The application discloses a high-capacity resin-based hard carbon material and a preparation method and application thereof, and the method for preparing the hard carbon material effectively avoids flammable gas risks, is safe and controllable in process, has the advantages of low cost and high efficiency, and is suitable for large-scale industrial application. The high-capacity resin-based hard carbon material prepared by the application has excellent lithium / sodium / potassium storage performance, and provides a new technical path for the development of lithium / sodium / potassium ion battery negative materials. The high-capacity resin-based hard carbon material prepared based on a liquid phase sealing technology utilizes the flow characteristics of liquid resin material before curing to uniformly coat the surface of selected activated carbon material, and converts the open pore structure of the activated carbon material into a closed pore structure. The method replaces the traditional gas phase sealing technology, avoids the safety risks of flammable gas carbon sources, is simple and controllable in process, and is easy to scale up production; and the treatment in a reducing atmosphere is selective, and can further optimize surface defects, improve the first coulomb efficiency and cycle stability.

Description

Technical Field

[0001] This invention relates to the field of battery anode material preparation technology, specifically to a high-capacity resin-based hard carbon material, its preparation method, and its application. Background Technology

[0002] As the global energy structure transitions towards cleaner and lower-carbon energy, the development and utilization of renewable energy sources such as wind and solar power are expanding rapidly. However, the inherent intermittency and volatility of renewable energy make the development of efficient, low-cost, and long-life grid-scale energy storage technologies crucial for achieving sustainable development. Among numerous energy storage solutions, sodium / potassium ion batteries (SIBs) are considered an ideal candidate to meet large-scale energy storage needs, following lithium-ion batteries, due to the extremely high abundance and wide distribution of sodium / potassium resources in the Earth's crust and their low extraction costs.

[0003] In the anode material system of sodium / potassium ion batteries (including intercalation, conversion, and alloy types), hard carbon (HC), as a typical intercalation material, has become the anode material closest to commercial application due to its advantages such as high theoretical specific capacity, low sodium intercalation potential, excellent cycle stability, and abundant raw material sources. However, unmodified hard carbon materials usually face the problem of low reversible capacity, making it difficult to meet the requirements of high energy density batteries.

[0004] Existing research indicates that the lithium / sodium / potassium storage capacity of hard carbon largely depends on the volume of closed pores (i.e., plateau capacity) in its microstructure. To improve capacity, current fabrication processes primarily aim to optimize the closed-pore structure by controlling the degree of crosslinking in the precursor to suppress excessive growth of graphite crystallites during carbonization. However, these methods have limited precision in controlling the microstructure, often failing to achieve precise customization of the number and size distribution of closed pores while ensuring structural stability. Consequently, the lithium / sodium / potassium storage potential of hard carbon materials remains largely untapped.

[0005] Therefore, developing an effective and controllable process to precisely construct abundant closed-cell structures as active sites for lithium / sodium / potassium storage, thereby preparing hard carbon anode materials with high reversible capacity, is a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing high-capacity resin-based hard carbon materials, effectively solving the technical problems existing in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution.

[0008] A method for preparing a high-capacity resin-based hard carbon material, characterized by comprising the following steps: S1. Mix the activated carbon material with the liquid resin material and stir evenly so that the liquid resin material fully wets the open-pore structure of the activated carbon material to form mixture A; S2. Based on S1, mixture A is pre-carbonized by heating under an inert atmosphere for 1 to 1.5 hours to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is further heated under an inert atmosphere for high-temperature carbonization treatment for 2 to 2.5 hours to obtain a carbonized sample. S4. Based on S3, the carbonized sample is subjected to high-temperature reduction treatment in a reducing atmosphere for 10-15 hours to obtain hard carbon material.

[0009] Preferably, in step S1, the mass ratio of activated carbon material to liquid resin material is 1~5:10.

[0010] Preferably, in step S1, the activated carbon material is any one or a combination of at least two of YP50F type activated carbon, wood-based activated carbon, or fruit peel activated carbon; the liquid resin material is any one or a combination of at least two of epoxy resin, phenolic resin, or polyurethane.

[0011] Preferably, in step S2, the inert atmosphere for pre-carbonization is any one or a combination of at least two of argon, nitrogen, and carbon dioxide, and the pre-carbonization temperature is 500-700℃.

[0012] Preferably, in step S3, the inert atmosphere for the high-temperature carbonization treatment is argon, the high-temperature carbonization temperature is 800-1500℃, and the carbonization time is 1-3 h.

[0013] Preferably, in step S4, the reducing atmosphere is a mixture of hydrogen and argon, wherein the volume ratio of argon to hydrogen is 5~10:1, and the reducing temperature is 700-900℃.

[0014] A high-capacity resin-based hard carbon material, characterized in that it is obtained by any one of the preparation methods described above.

[0015] Preferably, the interlayer spacing of the hard carbon material is 0.34-0.37 nm; the La of the hard carbon material is 2.0-4.0 nm; and the closed-cell specific surface area of ​​the hard carbon material is 200-900 m². 2 g -1 The hard carbon material has a pore size of 1.2-2.0 nm and a pore volume of 0.005-0.05 cm³. 3 g -1 The porosity of the hard carbon material is 0.05-0.12.

[0016] An application of a high-capacity resin-based hard carbon material, characterized in that: the hard carbon material is used to prepare a negative electrode material for lithium-ion batteries, sodium-ion batteries, or potassium-ion batteries.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The method for preparing hard carbon materials in this invention effectively avoids the risk of flammable gases, ensures process safety and controllability, and combines the advantages of low cost and high efficiency, making it suitable for large-scale industrial applications. The high-capacity resin-based hard carbon material prepared by this method has excellent lithium / sodium / potassium storage performance, providing a new technical path for the development of lithium / sodium / potassium ion battery anode materials. The high-capacity resin-based hard carbon material prepared by this invention is based on liquid phase sealing technology. By utilizing the flow characteristics of liquid resin material before curing, the surface of selected activated carbon material is uniformly coated, transforming the open-pore structure of the activated carbon material into a closed-pore structure. The prepared hard carbon material has high reversible capacity in battery anode materials. This method replaces the traditional gas phase sealing technology, avoids the safety risks of flammable gas carbon sources, and has a simple and controllable process that is easy to scale up for production. At the same time, selective treatment in a reducing atmosphere can further optimize surface defects and improve the initial coulombic efficiency and cycle stability. Attached Figure Description

[0018] Figure 1 The nitrogen adsorption-desorption curves are for the hard carbon materials prepared in Examples 2-7 of this invention.

[0019] Figure 2 Gas adsorption-desorption curves and pore size distribution diagrams of the hard carbon materials prepared in Examples 3-7 of this invention.

[0020] Figure 3 The Raman spectra and fitting results of the hard carbon materials prepared in Examples 3-7 of this invention are shown.

[0021] Figure 4 The diagram shows the pore structure characteristics of the hard carbon materials prepared in Examples 3-7 of this invention.

[0022] Figure 5 The charge-discharge curves and capacity data of the hard carbon materials prepared in Examples 3-7 of this invention in lithium / sodium / potassium ion half-cells are shown.

[0023] Figure 6 Sodium-ion and potassium-ion full cells prepared from the hard carbon material of Example 5 of the present invention were used in a process involving 0.1 A g. -1 Capacity display after 500 cycles at current density.

[0024] Figure 7 This is a charge-discharge curve of the hard carbon material prepared in Example 2 of the present invention in a lithium half-cell. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0028] A method for preparing a high-capacity resin-based hard carbon material, characterized by comprising the following steps: S1. Mix the activated carbon material with the liquid resin material and stir evenly so that the liquid resin material fully wets the open-pore structure of the activated carbon material to form mixture A; In this embodiment, the mass ratio of activated carbon material to liquid resin material is 1~5:10; the activated carbon material is any one or a combination of at least two of YP50F type activated carbon, wood-based activated carbon, or fruit peel activated carbon; the liquid resin material is any one or a combination of at least two of epoxy resin, phenolic resin, or polyurethane.

[0029] S2. Based on S1, mixture A is pre-carbonized by heating under an inert atmosphere for 1 to 1.5 hours to obtain a pre-carbonized sample. In this embodiment, the inert atmosphere for pre-carbonization is any one or a combination of at least two of argon, nitrogen, and carbon dioxide, and the pre-carbonization temperature is 500-700℃.

[0030] S3. Based on S2, the pre-carbonized sample is further heated under an inert atmosphere for high-temperature carbonization treatment for 2 to 2.5 hours to obtain a carbonized sample. In this embodiment, the inert atmosphere for the high-temperature carbonization treatment is argon, the high-temperature carbonization temperature is 800-1500℃, and the carbonization time is 1-3 h.

[0031] S4. Based on S3, the carbonized sample is subjected to high-temperature reduction treatment in a reducing atmosphere for 10-15 hours to obtain hard carbon material.

[0032] In this embodiment, the reducing atmosphere is a mixture of hydrogen and argon, wherein the volume ratio of argon to hydrogen is 5~10:1, and the reducing temperature is 700-900℃.

[0033] The hard carbon material is prepared by the above method and is used to prepare negative electrode materials for lithium-ion batteries, sodium-ion batteries or potassium-ion batteries.

[0034] The interlayer spacing of the hard carbon material of this invention is 0.34-0.37 nm; the La content of the hard carbon material is 2.0-4.0 nm; and the closed-cell specific surface area of ​​the hard carbon material is 200-900 m². 2 g -1 The pore size of hard carbon materials is 1.2-2.0 nm; the pore volume of hard carbon materials is 0.005-0.05 cm³. 3 g -1 The porosity of hard carbon materials is 0.05-0.12.

[0035] Example 2: Preparation of high lithium storage capacity hard carbon materials The difference between this embodiment and Embodiment 1 lies in some differences in the preparation methods of the high-capacity resin-based hard carbon material. The specific steps of the preparation method for the high-capacity resin-based hard carbon material in this embodiment are as follows: S1. Mix fruit peel activated carbon and liquid phenolic resin at a mass ratio of 1:10 for 1 hour to allow the liquid phenolic resin to fully impregnate the open-pore structure of the fruit peel activated carbon and form a uniform mixture A. S2. Based on S1, mixture A is placed in a tube furnace and heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 600°C at a heating rate, and the sample was pre-carbonized for 1.5 hours to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000°C at a certain heating rate, and carbonized for 2 hours to obtain a carbonized sample.

[0036] S4. Based on S3, the carbonized sample was treated at 900°C for 12 h in a hydrogen reducing atmosphere (Ar / H2 volume ratio 5:1) to obtain a hard carbon material. This hard carbon material is a high lithium storage capacity hard carbon material.

[0037] The hard carbon material prepared in this embodiment has an interlayer spacing of 0.344 nm, a La content of 2.1 nm, and a closed-cell specific surface area of ​​297.9 m². 2 g -1 The pore size is 1.42 nm and the pore volume is 0.009 cm³. 3 g -1 The porosity is 0.057.

[0038] Example 3: Preparation of high sodium / potassium storage capacity hard carbon materials The difference between this embodiment and Embodiment 1 lies in some differences in the preparation methods of the high-capacity resin-based hard carbon material. The specific steps of the preparation method for the high-capacity resin-based hard carbon material in this embodiment are as follows: S1. Mix YP50F activated carbon and liquid epoxy resin at a mass ratio of 1:10 for 1 hour to allow the liquid epoxy resin to fully impregnate the open-pore structure of YP50F activated carbon and form a uniform mixture A. S2. Based on S1, mixture A is placed in a tube furnace and heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 600°C at a heating rate, and the sample was pre-carbonized for 1 h to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1500°C at a certain heating rate, and carbonized for 2 hours to obtain a carbonized sample.

[0039] S4. Based on S3, the carbonized sample was treated at 700°C for 12 h in a hydrogen reducing atmosphere (Ar / H2 volume ratio 8:1) to obtain a hard carbon material. This hard carbon material is a hard carbon material with high sodium / potassium storage capacity.

[0040] The hard carbon material prepared in this embodiment has an interlayer spacing of 0.345 nm, a La content of 2.6 nm, and a closed-cell specific surface area of ​​488.9 m². 2 g -1 The pore size is 1.54 nm and the pore volume is 0.026 cm³. 3 g -1 The porosity is 0.057.

[0041] Example 4: Preparation of high sodium / potassium storage capacity hard carbon materials The difference between this embodiment and Embodiment 1 lies in some differences in the preparation methods of the high-capacity resin-based hard carbon material. The specific steps of the preparation method for the high-capacity resin-based hard carbon material in this embodiment are as follows: S1. Mix YP50F activated carbon and liquid phenolic resin at a mass ratio of 2:10 for 1 hour to allow the liquid phenolic resin to fully impregnate the open-pore structure of YP50F activated carbon and form a uniform mixture A. S2. Based on S1, mixture A is placed in a tube furnace and heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 600°C at a heating rate, and the sample was pre-carbonized for 1 h to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1:500°C at a heating rate, and carbonized for 2 h to obtain a carbonized sample.

[0042] S4. Based on S3, the carbonized sample was treated at 800°C for 11 h in a hydrogen reducing atmosphere (Ar / H2 volume ratio 9:1) to obtain a hard carbon material. This hard carbon material is a hard carbon material with high sodium / potassium storage capacity.

[0043] The hard carbon material prepared in this embodiment has an interlayer spacing of 0.355 nm, a La content of 3.2 nm, and a closed-cell specific surface area of ​​491.9 m². 2 g -1 The pore size is 1.72 nm, and the pore volume is 0.032 cm³. 3 g -1 The porosity is 0.077.

[0044] Example 5: Preparation of high sodium / potassium storage capacity hard carbon materials The difference between this embodiment and Embodiment 1 lies in some differences in the preparation methods of the high-capacity resin-based hard carbon material. The specific steps of the preparation method for the high-capacity resin-based hard carbon material in this embodiment are as follows: S1. Mix YP50F activated carbon and liquid phenolic resin at a mass ratio of 3:10 for 1 hour to allow the liquid phenolic resin to fully impregnate the open-pore structure of YP50F activated carbon and form a uniform mixture A. S2. Based on S1, mixture A is placed in a tube furnace and heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 500°C at a heating rate, and the sample was pre-carbonized for 1.5 h to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1500°C at a certain heating rate, and carbonized for 2 hours to obtain a carbonized sample.

[0045] S4. Based on S3, the carbonized sample was treated at 800°C for 11 h in a hydrogen reducing atmosphere (Ar / H2 volume ratio 9:1) to obtain a hard carbon material. This hard carbon material is a hard carbon material with high sodium / potassium storage capacity.

[0046] The hard carbon material prepared in this embodiment has an interlayer spacing of 0.357 nm, a La content of 3.4 nm, and a closed-cell specific surface area of ​​693.1 m². 2 g -1The pore size is 1.83 nm, and the pore volume is 0.038 cm³. 3 g -1 The porosity is 0.084.

[0047] Example 6: Preparation of high sodium / potassium storage capacity hard carbon materials The difference between this embodiment and Embodiment 1 lies in some differences in the preparation methods of the high-capacity resin-based hard carbon material. The specific steps of the preparation method for the high-capacity resin-based hard carbon material in this embodiment are as follows: S1. Mix YP50F activated carbon and liquid phenolic resin at a mass ratio of 4:10 for 1 hour to allow the liquid phenolic resin to fully impregnate the open-pore structure of YP50F activated carbon and form a uniform mixture A. S2. Based on S1, mixture A is placed in a tube furnace and heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 700°C at a heating rate, and the sample was pre-carbonized for 1 h to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1500°C at a certain heating rate, and carbonized for 2 hours to obtain a carbonized sample.

[0048] S4. Based on S3, the carbonized sample was treated at 700°C for 14 h in a hydrogen reducing atmosphere (Ar / H2 volume ratio 9:1) to obtain a hard carbon material. This hard carbon material is a hard carbon material with high sodium / potassium storage capacity.

[0049] The hard carbon material prepared in this embodiment has an interlayer spacing of 0.363 nm, a La content of 3.5 nm, and a closed-cell specific surface area of ​​813.2 m². 2 g -1 The pore size is 1.92 nm, and the pore volume is 0.041 cm³. 3 g -1 The porosity is 0.096.

[0050] Example 7: Preparation of high sodium / potassium storage capacity hard carbon materials The difference between this embodiment and Embodiment 1 lies in some differences in the preparation methods of the high-capacity resin-based hard carbon material. The specific steps of the preparation method for the high-capacity resin-based hard carbon material in this embodiment are as follows: S1. Mix YP50F activated carbon and liquid phenolic resin at a mass ratio of 5:10 for 1 hour to allow the liquid phenolic resin to fully impregnate the open-pore structure of YP50F activated carbon and form a uniform mixture A. S2. Based on S1, mixture A is placed in a tube furnace and heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 600°C at a heating rate, and the sample was pre-carbonized for 1.5 h to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is heated at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1300°C at a certain heating rate, and carbonized for 2 hours to obtain a carbonized sample.

[0051] S4. Based on S3, the carbonized sample was treated at 800°C for 11 h in a hydrogen reducing atmosphere (Ar / H2 volume ratio 10:1) to obtain a hard carbon material. This hard carbon material is a hard carbon material with high sodium / potassium storage capacity.

[0052] The hard carbon material prepared in this embodiment has an interlayer spacing of 0.368 nm, a La content of 3.8 nm, and a closed-cell specific surface area of ​​875.6 m². 2 g -1 The pore size is 1.98 nm, and the pore volume is 0.049 cm³. 3 g -1 The porosity is 0.117.

[0053] Comparative Example 1: Preparation of Traditional Hard Carbon Materials This comparative example does not employ liquid-phase sealing technology; instead, it uses directly carbonized phenolic resin as a control. The specific steps are as follows: S1. Place the phenolic resin precursor directly in an argon atmosphere at 5°C for 1 minute. -1 Pre-carbonization treatment is completed by heating to 600°C and carbonizing for 1 hour; S2. Place the above pre-carbonized material in an argon atmosphere at 5°C for 1 minute. -1 The carbonization process was completed by heating to 1500°C for 2 hours, thus preparing hard carbon materials.

[0054] Negative electrode preparation The hard carbon material (active material), super P (conductive agent), and sodium carboxymethyl cellulose (CMC, binder) prepared in Examples 2-7 and Comparative Example 1 were weighed and mixed at a mass ratio of 8:1:1 (total mass of the mixture was 0.2 g). An appropriate amount of deionized water was added as a dispersion solvent, and the mixture was thoroughly ground and stirred to form a uniform and stable electrode slurry. Subsequently, the slurry was uniformly coated onto the surface of a copper foil current collector using a coating process, and then dried in a vacuum drying oven at 80°C for 12 h to remove the solvent. After vacuum drying at 80°C for 12 h, the slurry was cut into hard carbon negative electrode sheets with a diameter of 12 mm.

[0055] Positive electrode preparation For full-cell testing, different cathodes were matched for different battery systems: lithium-ion batteries used lithium iron phosphate (LFP) as the cathode active material; sodium-ion batteries used NFPP (sodium iron phosphate) or similar materials as the cathode; and potassium-ion batteries used Prussian blue (PB) as the cathode.

[0056] Positive electrode preparation: The positive electrode active material, conductive agent, and binder are mixed at a mass ratio of 8:1:1, and N-methyl-2-pyrrolidone solvent is added to form a slurry. This slurry is coated onto aluminum foil, vacuum dried at 120°C for 12 hours, and then cut into positive electrode sheets. During full cell assembly, the N / P ratio is controlled to be approximately 1.1-1.2.

[0057] Performance testing Using the negative electrode sheets prepared in Examples 2-7 and Comparative Example 1 as negative electrodes, and lithium, sodium, or potassium metal as counter electrodes, and 1 M LiPF6 in EC / DEC, 0.8 M NaPF6 in EC / DEC, or 0.8 M KPF6 in EC / DEC (volume ratio 1:1) as electrolytes, CR2032 coin cells were assembled in an inert atmosphere. The coin cell structure includes a positive electrode shell (stainless steel), a negative electrode shell (stainless steel), a gasket (stainless steel), a spring (stainless steel), a hard carbon electrode, a sodium sheet, an electrolyte, and a separator (glass fiber).

[0058] The test was conducted at 25°C, with a half-cell discharge cutoff voltage of 0.002 V and a charging cutoff voltage of 2 V; the voltage window for the full cell was set according to the actual system. Key performance data are shown in Tables 1 and 2. 1C = 200 mAh g -1 .

[0059]

[0060] Table 1

[0061] Table 2 Figure 1 This figure shows the nitrogen adsorption-desorption curves of the activated carbon material used in Examples 2-7 of this application. The type I adsorption-desorption isotherm demonstrates the high specific surface area (1584 m²) of the activated carbon template. 2 The abundance of nanoporous structures (·g⁻¹) provides a foundation for liquid-phase pore sealing.

[0062] Figure 2 (a) to Figure 2 (c) shows the gas adsorption-desorption curves and pore size distribution of the high sodium / potassium storage capacity hard carbon materials prepared in Examples 3-7 of this application. Figure 2 The adsorption behavior of nitrogen and carbon dioxide in samples with different activated carbon / resin mass ratios was compared, showing that the closed-pore structure was optimized with increasing ratio, and the micropore distribution was concentrated in the range of 0.50-0.78 nm. Meanwhile, the nitrogen and carbon dioxide adsorption-desorption curves of the sample in Example 3 showed that its specific surface area was reduced to 11.7 m²·g⁻¹ compared to the original YP50F porous carbon, and the micropore volume was 0.009 cm³·g⁻¹, indicating that the liquid-phase sealing technology effectively transformed open pores into closed pores.

[0063] Figure 3 The Raman spectra and fitting results are shown for the high sodium / potassium storage capacity hard carbon materials prepared in Examples 3-7 of this application. D1 / I G The values ​​were 1.76 (Example 3), 1.80 (Example 4), 1.88 (Example 5), 1.85 (Example 6), and 1.87 (Example 7), respectively. D4 / I G The values ​​were 0.31 (Example 3), 0.25 (Example 4), 0.28 (Example 5), 0.26 (Example 6), and 0.27 (Example 7), respectively.

[0064] Figure 4 To further resolve the pore structure characteristics of high sodium / potassium storage capacity hard carbon materials, small-angle neutron scattering (SANS) tests were conducted when the scattering vector was in the range of 0.005–0.1 Å. -1 At that time, a shoulder peak appeared in the scattering intensity curve, corresponding to the microporous structure characteristics of hard carbon materials. Further fitting analysis was performed on the SANS spectrum, from... Figure 4 It can be seen that the closed-pore specific surface area of ​​the hard carbon sample first increases and then decreases, with values ​​of 468.9 m². 2 g -1 (Example 3), 813.2 m 2 g -1 (Example 4), 693.1 m 2 g -1 (Example 5), 471.9 m 2 g -1 (Example 6), 277.9 m 2 g -1 (Example 7). With increasing activated carbon / resin mass ratio, the pore size showed an expanding trend, reaching 7.34 Å (Example 3), 7.87 Å (Example 4), 8.64 Å (Example 5), 9.01 Å (Example 6), and 9.15 Å (Example 7), respectively, and exhibited a wide pore size distribution. The porosity (Vpore) showed the same trend of first increasing and then decreasing (Vpore, 0.077 (Example 3), 0.096 (Example 4), 0.117 (Example 5), 0.077 (Example 6), and 0.084 (Example 7). Figure 5 Charge-discharge curves and capacity data of sodium / potassium ion half-cells made of hard carbon materials in Examples 3-7 are shown. Example 5 showed the best performance, with a sodium storage capacity of 474.8 mAh g⁻¹. -1 Potassium storage capacity: 463.0 mAh g -1Furthermore, the platform capacity accounts for a high proportion (e.g., the sodium platform capacity is 363.8 mAh g). -1 ).

[0065] like Figure 6 As shown, sodium-ion and potassium-ion full cells prepared from the hard carbon material obtained in Example 5 were tested at 0.1 A g. -1 The capacity retention rates after 500 cycles at current density were 95.7% and 81.1%, respectively, demonstrating excellent cycle stability and verifying that the hard carbon material of this invention has excellent practical application capabilities.

[0066] like Figure 7 The charge-discharge curves of the hard carbon material prepared in Example 2 in a lithium half-cell are shown, with a lithium storage capacity of 460 mAh g. -1 At 1000mA g -1 The capacity is still 155 mAh g at current density. -1 .

[0067] The method for preparing hard carbon materials according to this invention effectively avoids the risk of flammable gases, ensures process safety and controllability, and combines the advantages of low cost and high efficiency, making it suitable for large-scale industrial applications. The high-capacity resin-based hard carbon material prepared by this method exhibits excellent lithium / sodium / potassium storage performance, providing a new technical path for the development of anode materials for lithium / sodium / potassium ion batteries.

[0068] This invention relates to a high-capacity resin-based hard carbon material prepared using liquid-phase sealing technology. Utilizing the flow characteristics of liquid resin before curing, the surface of selected activated carbon material is uniformly coated, transforming the open-pore structure of the activated carbon material into a closed-pore structure. The resulting hard carbon material exhibits high reversible capacity in battery anode materials. This method replaces traditional gas-phase sealing technology, avoiding the safety risks associated with flammable gas carbon sources. The process is simple, controllable, and easily scaled up for production. Furthermore, selective treatment in a reducing atmosphere further optimizes surface defects, improving initial coulombic efficiency and cycle stability.

[0069] According to the experimental results of performance testing, the high lithium storage capacity hard carbon material (Example 2) prepared based on liquid phase sealing technology has a lithium storage capacity of 20 mA g. -1 At current density, the specific capacity of the lithium-ion half-cell reaches as high as 460.0 mAh g⁻¹. -1 Meanwhile, in the full-cell system, this material also exhibits excellent long-cycle stability (0.1 A g). -1 Capacity retention of 69.6% after 500 cycles at current density) and rate performance (1 A g) -1 Capacity reaches 283.6 mAh g at current density. -1High sodium / potassium storage capacity hard carbon material prepared based on liquid phase sealing technology (Example 3 or Example 3), at 20 mA g -1 At the specified current density, the sodium storage capacity reaches 474.8 mAh g⁻¹, and the potassium storage capacity reaches 463.0 mAh g⁻¹. The high-capacity resin-based hard carbon anode material provided by this invention has broad application prospects and is expected to be widely used in the field of alkali metal ion batteries.

[0070] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any modifications, equivalent changes, improvements, etc., made in accordance with the claims of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high-capacity resin-based hard carbon material, characterized in that, Includes the following steps: S1. Mix the activated carbon material with the liquid resin material and stir evenly so that the liquid resin material fully wets the open-pore structure of the activated carbon material to form mixture A; S2. Based on S1, mixture A is pre-carbonized by heating under an inert atmosphere for 1 to 1.5 hours to obtain a pre-carbonized sample. S3. Based on S2, the pre-carbonized sample is further heated under an inert atmosphere for high-temperature carbonization treatment for 2 to 2.5 hours to obtain a carbonized sample. S4. Based on S3, the carbonized sample is subjected to high-temperature reduction treatment in a reducing atmosphere for 10-15 hours to obtain hard carbon material.

2. The method for preparing a high-capacity resin-based hard carbon material according to claim 1, characterized in that, In step S1, the mass ratio of activated carbon material to liquid resin material is 1~5:

10.

3. The method for preparing a high-capacity resin-based hard carbon material according to claim 2, characterized in that, In step S1, the activated carbon material is any one or a combination of at least two of YP50F type activated carbon, wood-based activated carbon, or fruit peel activated carbon; the liquid resin material is any one or a combination of at least two of epoxy resin, phenolic resin, or polyurethane.

4. The method for preparing a high-capacity resin-based hard carbon material according to claim 3, characterized in that, In step S2, the inert atmosphere for pre-carbonization is any one or a combination of at least two of argon, nitrogen, and carbon dioxide, and the pre-carbonization temperature is 500-700℃.

5. The method for preparing a high-capacity resin-based hard carbon material according to claim 4, characterized in that, In step S3, the inert atmosphere for the high-temperature carbonization treatment is argon, the high-temperature carbonization temperature is 800-1500℃, and the carbonization time is 1-3 h.

6. The method for preparing a high-capacity resin-based hard carbon material according to claim 5, characterized in that, In step S4, the reducing atmosphere is a mixture of hydrogen and argon, wherein the volume ratio of argon to hydrogen is 5~10:1, and the reducing temperature is 700-900℃.

7. A high-capacity resin-based hard carbon material, characterized in that, It is obtained by the preparation method according to any one of claims 1 to 6.

8. The high-capacity resin-based hard carbon material according to claim 7, characterized in that, The interlayer spacing of the hard carbon material is 0.34-0.37 nm; the La content of the hard carbon material is 2.0-4.0 nm; and the closed-cell specific surface area of ​​the hard carbon material is 200-900 m². 2 g -1 The hard carbon material has a pore size of 1.2-2.0 nm and a pore volume of 0.005-0.05 cm³. 3 g -1 The porosity of the hard carbon material is 0.05-0.

12.

9. The application of a high-capacity resin-based hard carbon material according to claim 8, characterized in that: The hard carbon material is used to prepare negative electrode materials for lithium-ion batteries, sodium-ion batteries, or potassium-ion batteries.

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