A kind of porous carbon, porous carbon preparation method, negative pole piece and lithium ion battery

Abstract

This invention discloses a porous carbon, a method for preparing porous carbon, an anode sheet, and a lithium-ion battery. The porous carbon and its preparation method for this silicon-carbon anode material utilize inexpensive and widely available high-sulfur pitch as raw material. Crosslinking is achieved by adding ion-exchange resin-type crosslinking agents and organic sulfides, followed by two-step heat treatment, thus realizing the efficient preparation of porous carbon materials. The key to this method lies in: adding a small amount of ion-exchange resin-type crosslinking agent to promote the formation of a stable hard carbon framework structure in the high-sulfur pitch after heat treatment; simultaneously, the precise control of the introduction, type, and amount of organic sulfides effectively regulates the specific surface area, micropore ratio, and pore size distribution of the obtained porous carbon, ultimately producing a porous carbon material with high specific surface area, high micropore ratio, high pore volume, and excellent conductivity. When this porous carbon material is used as a substrate for silicon-carbon anode materials, it can significantly improve the overall performance of the battery, and the preparation process is simple.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery preparation, and in particular to a porous carbon, a method for preparing porous carbon, a negative electrode sheet, and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries (LIBs), as advanced portable energy storage systems, have driven the rapid development of electric vehicles (EVs) in recent years. Compared to gasoline vehicles (GCs), EVs are more environmentally friendly, energy-efficient, and economical. However, a prominent drawback of current EVs is their short driving range, making improving the energy density of lithium batteries a crucial research direction for the lithium battery industry.

[0003] Currently, there are various materials used for lithium-ion battery anodes. Among them, artificial graphite has become the mainstream anode material due to its superior cycle performance and safety. However, the theoretical capacity of graphite anodes is only 372 mAh / g, and the capacity of commercially available artificial graphite anodes is already close to its theoretical capacity, making it very difficult to further increase its energy density. Silicon materials, on the other hand, have a theoretical capacity of 4200 mAh / g, more than ten times that of graphite anodes, and possess a much higher energy density. However, silicon materials suffer from poor conductivity and large volume expansion, which limits their commercial application.

[0004] Numerous optimization efforts have been undertaken to address the issues of poor conductivity and large volume expansion in silicon anodes. Currently, most next-generation silicon anode modification methods utilize porous carbon as a substrate material for nano-silicon deposition. Depositing nano-silicon vapor phase within a porous carbon framework effectively alleviates the volume expansion stress of silicon during lithium battery cycling, preventing anode pulverization and detachment. Simultaneously, carbon materials enhance conductivity, significantly improving performance when used as a lithium battery anode material. For example, patent CN118359182A discloses a porous carbon silicon-carbon anode material and its preparation method. By mixing polyvinyl alcohol (PVA) with ammonium sulfate and drying it, a porous carbon precursor is obtained. During carbonization, PVA forms porous carbon silicon-carbon anode material under a nitrogen atmosphere, while ammonium sulfate decomposes at high temperature to produce ammonia, nitrogen, sulfur dioxide, and water vapor. This gas generation process impacts the morphology of the carbon material formed by PVA under a nitrogen atmosphere, resulting in a porous carbon material with both micropores and mesopores and a high specific surface area. However, the high cost of polyvinyl alcohol and ammonium sulfate raw materials used in this method, coupled with the low overall yield, results in high production costs. Furthermore, the porous carbon synthesized using this process has a relatively low specific surface area and its pore structure is difficult to effectively control, limiting its performance improvement when used as a substrate material for silicon deposition. For example, patent CN114122352A discloses a method for preparing modified porous carbon. This method involves adding a binder, conductive carbon black, and carbon nanotubes to water to obtain a mixed solution. The solution is then spray-dried at 180°C–200°C to obtain a porous carbon precursor. The precursor is then heat-treated to obtain a porous carbon material. Finally, a catalyst is doped onto the surface of the porous carbon material for 3–5 minutes to obtain modified porous carbon. However, this method is cumbersome, and the prepared porous carbon has a low specific surface area and its pore structure is difficult to effectively control, limiting its performance improvement when used as a substrate material for silicon deposition. Summary of the Invention

[0005] The purpose of this invention is to provide porous carbon, a method for preparing porous carbon, a negative electrode sheet, and a lithium-ion battery, thereby improving the specific surface area, micropore ratio, and pore volume of porous carbon materials.

[0006] This invention discloses a method for preparing porous carbon, the method comprising: Under a protective atmosphere, the sulfurized crosslinked asphalt composite is subjected to a first heat treatment, which causes the organic sulfur compounds to undergo a crosslinking reaction with the high-sulfur asphalt to form sulfurized asphalt. Under a protective atmosphere, the sulfurized asphalt is subjected to a second heat treatment, which causes the sulfurized asphalt to carbonize and form a porous carbon material.

[0007] Furthermore, the sulfur content in the high-sulfur asphalt is 4%-8%, and the softening point of the high-sulfur asphalt is 50-80°C; and / or, the first heat treatment includes: heating the vulcanized crosslinked asphalt composite to 120-160°C and holding it at that temperature for 3-5 hours; and / or, the second heat treatment includes: heating the vulcanized asphalt to 1250-1450°C and holding it at that temperature for 2-4 hours.

[0008] Furthermore, the ion exchange resin crosslinking agent includes at least one of cation exchange resin and anion exchange resin.

[0009] Furthermore, the cation exchange resin includes at least one of a strong acid styrene cation exchange resin and a weak acid acrylic cation exchange resin; the anion exchange resin includes a weak acid acrylic anion exchange resin.

[0010] Furthermore, the organic sulfide includes at least one of thiols, sulfoxides, and sulfones.

[0011] Furthermore, the thiol is ethanethiol, butanethiol, or cyclohexanethiol; the sulfoxide type sulfide is dimethyl sulfoxide, diethyl sulfoxide, cyclobutane sulfoxide, or diphenyl sulfoxide; and the sulfone type sulfide is diethyl sulfone, cyclobutane sulfone, or diphenyl sulfone.

[0012] Furthermore, in the vulcanized crosslinked asphalt composite, the high-sulfur asphalt accounts for 60%-70% by mass, the ion exchange resin crosslinking agent accounts for 10%-15% by mass, and the organic sulfide accounts for 15%-25% by mass.

[0013] Furthermore, the present invention also provides a porous carbon, prepared using the above-described porous carbon preparation method, wherein the porous carbon has a micropore ratio of greater than or equal to 85% and a micropore volume of greater than or equal to 0.6 cm³. 3 / g, specific surface area greater than or equal to 1500m² 2 / g.

[0014] Furthermore, the present invention also provides a negative electrode sheet, wherein the negative electrode sheet includes the aforementioned porous carbon.

[0015] Furthermore, the present invention also provides a lithium-ion battery, wherein the lithium-ion battery includes the above-mentioned negative electrode sheet.

[0016] Compared with the prior art, the present invention has at least the following technical effects: By adding a small amount of ion-exchange resin crosslinking agent, a stable hard carbon framework structure is formed in high-sulfur asphalt after heat treatment. Simultaneously, the introduction of organic sulfides and precise control of their type and dosage effectively regulate the specific surface area, micropore ratio, and pore size distribution of the resulting porous carbon, ultimately producing a porous carbon material with high specific surface area, high micropore ratio, high pore volume, and excellent conductivity. When used as a substrate for silicon-carbon anode materials, this porous carbon material significantly improves the overall performance of the battery, and the preparation process is simple and easily scalable. Attached Figure Description

[0017] Figure 1 This is a simplified flowchart illustrating the porous carbon preparation method in Embodiment 1 of the present invention. Detailed Implementation

[0018] The following description, with reference to schematic diagrams, illustrates a porous carbon, a method for preparing porous carbon, a negative electrode sheet, and a lithium-ion battery according to the present invention. Preferred embodiments of the invention are shown. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0019] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0020] Example 1 This embodiment discloses a method for preparing porous carbon, the method comprising: S1. Mix the high-sulfur asphalt, ion exchange resin crosslinking agent and organic sulfide to obtain a sulfurized crosslinked asphalt composite; S2. Under a protective atmosphere, the sulfurized crosslinked asphalt composite is subjected to a first heat treatment, so that the organic sulfur compound and the high sulfur asphalt undergo a crosslinking reaction to form sulfurized asphalt; S3. Under a protective atmosphere, the sulfurized asphalt is subjected to a second heat treatment, so that the sulfurized asphalt is carbonized to form a porous carbon material.

[0021] In this embodiment, by adding a small amount of ion-exchange resin crosslinking agent, a stable hard carbon framework structure is formed in the high-sulfur asphalt after heat treatment. Simultaneously, the introduction of organic sulfides and the precise control of their type and amount effectively regulate the specific surface area, micropore ratio, and pore size distribution of the resulting porous carbon, ultimately producing a porous carbon material with high specific surface area, high micropore ratio, high pore volume, and excellent conductivity. When this porous carbon material is used as a substrate for silicon-carbon anode materials, it improves the overall performance of the battery. Furthermore, the preparation process is simple and easily scalable.

[0022] In step S1, the sulfur content in the high-sulfur asphalt is 4%-8%, for example, 5%, 7%, and 7.5%. The softening point of the high-sulfur asphalt is 50-80°C.

[0023] In this embodiment, the advantage of choosing the aforementioned high-sulfur asphalt is that: if the sulfur content is too low, the resulting pore structure will be insufficient, affecting the specific surface area of ​​the final porous carbon; if the sulfur content is too high, excessive sulfur will damage the integrity of the carbon skeleton structure during heat treatment, leading to a decrease in mechanical strength. A sulfur content of 4%-8% in the high-sulfur asphalt is a preferred choice.

[0024] The advantages of choosing the above softening point are as follows: A softening point that is too low will cause the asphalt to melt and flow prematurely in the early stages of heat treatment, making it difficult to maintain a stable precursor morphology; a softening point that is too high will hinder the thorough and uniform mixing of the raw materials, affecting the cross-linking reaction and pore structure formation. Therefore, a softening point of 50-80°C is the optimal choice for high-sulfur asphalt.

[0025] Furthermore, in step S1, when mixing to form a vulcanized crosslinked asphalt composite, the mass percentage of high-sulfur asphalt in the vulcanized crosslinked asphalt composite is 60%-70%, the mass percentage of ion exchange resin crosslinking agent is 10%-15%, and the mass percentage of organic sulfides is 15%-25%.

[0026] In one specific embodiment, based on a total amount of 100g, 60-70g of high-sulfur asphalt, 10-15g of ion exchange resin crosslinking agent, and 15-25g of organic sulfides are added to the sulfurized crosslinked asphalt composite.

[0027] By selecting high-sulfur asphalt, ion exchange resin crosslinking agent, and organic sulfides with the above-mentioned content and mixing them, a sulfurized crosslinked asphalt composite with a stable carbon skeleton structure, high thermal stability, and an appropriate amount of porosity can be obtained.

[0028] Furthermore, the ion exchange resin crosslinking agent includes at least one of cation exchange resin and anion exchange resin.

[0029] In one specific embodiment, the cation exchange resin includes at least one of a strongly acidic styrene cation exchange resin and a weakly acidic acrylic cation exchange resin; the anion exchange resin includes a weakly acidic acrylic anion exchange resin.

[0030] Furthermore, the organic sulfide is at least one of thiols, sulfoxides, and sulfones. For example, thiols, sulfoxides, or a mixture of sulfoxides and sulfones may be selected, or only thiols, sulfoxides, or sulfones may be selected.

[0031] In this embodiment, organic sulfides are used as pore-forming agents during the preparation process, and appropriately increasing the total amount of organic sulfides is beneficial to the formation of pore structures. By selecting different types (such as thiols, sulfoxides, and sulfones) and adjusting the amount added, and utilizing their decomposition characteristics during heat treatment, the specific surface area, micropore content, and pore size distribution of the final porous carbon material can be precisely controlled, thereby obtaining carbon-based materials with excellent electrochemical performance.

[0032] In one specific embodiment, when preparing 100g of vulcanized crosslinked asphalt composite, 65g of high-sulfur asphalt, 12g of ion exchange resin crosslinking agent, and 23g of organic sulfide are mixed. As another example, when preparing 100g of vulcanized crosslinked asphalt composite, 65g of high-sulfur asphalt, 15g of ion exchange resin crosslinking agent, 5g of thiol, and 15g of organic sulfide are mixed.

[0033] In this embodiment, when the above-mentioned amount of high-sulfur asphalt is used, the carbon source is sufficient, laying the foundation for the formation of a stable carbon skeleton. Its 4%-8% sulfur content decomposes moderately during heat treatment, which is beneficial for forming a uniform pore structure. Adding 10g-15g of ion exchange resin-type crosslinking agent can fully promote intermolecular crosslinking of the high-sulfur asphalt, improve the thermal stability of the carbon precursor, and prevent structural collapse during secondary heat treatment. Adding 15-25g of organic sulfides can further supplement the sulfur content of the system, working synergistically with the sulfur in the high-sulfur asphalt to build abundant pores during heat treatment. Through the above optimized ratio, the raw materials can fully react, and the pore structure of the final product can be effectively controlled. The resulting porous carbon material has a high specific surface area, uniform pore size distribution, and excellent mechanical strength, meeting the requirements for silicon-carbon anode material substrates. Furthermore, it has good process adaptability and is suitable for large-scale production.

[0034] In one specific embodiment, the thiol is ethanethiol, butanethiol, or cyclohexanethiol; the sulfoxide is dimethyl sulfoxide, diethyl sulfoxide, cyclobutane sulfoxide, or diphenyl sulfoxide; and the sulfone is diethyl sulfone, cyclobutane sulfone, or diphenyl sulfone.

[0035] In this embodiment, the first heat treatment includes heating the vulcanized crosslinked asphalt composite to 120-160°C and holding it at that temperature for 3-5 hours.

[0036] In this embodiment, the temperature of the first heat treatment needs to be reasonably selected according to the degree of cross-linking reaction. If the temperature is too low, the cross-linking reaction will be incomplete, affecting the subsequent formation of the carbon skeleton; if the temperature is too high, the organic sulfides will decompose prematurely, which is not conducive to the construction of uniform pores. Therefore, the preferred temperature for the first heat treatment is 120-160°C, for example: 122°C, 130°C, 140°C, 150°C.

[0037] The advantage of choosing to keep it warm for 3-5 hours is that the above-mentioned heat preservation time can allow the high sulfur asphalt to undergo a full sulfurization and cross-linking reaction with the cross-linking agent and organic sulfur compounds, making the precursor structure tend to be stable. It can also avoid excessive decomposition or volatilization of organic components due to excessive heat preservation time, resulting in uneven distribution of pore structure, pore collapse or reduced raw material utilization.

[0038] In one specific embodiment, the protective atmosphere is an inert gas, preferably nitrogen. Those skilled in the art can also select different inert gases, such as helium and neon, based on factors such as reaction protection effect, thermal stability, and thermal conductivity.

[0039] Furthermore, in this embodiment, the second heat treatment includes: heating the vulcanized crosslinked asphalt composite to 1250-1450°C and holding it at that temperature for 2-4 hours.

[0040] In this embodiment, the temperature of the second heat treatment needs to be selected based on the degree of carbonization and the formation of the pore structure. If the heat treatment temperature is too low, it will lead to insufficient carbonization, affecting the conductivity and mechanical strength of the material; if the temperature is too high, it will cause the pore structure to collapse, reducing the specific surface area, which is not conducive to the subsequent loading of nano-silicon. Therefore, the preferred temperature for the second heat treatment is 1250-1450°C, for example, 1251°C, 1260°C, 1300°C, 1400°C, or 1440°C.

[0041] The advantage of choosing to keep it warm for 2-4 hours is that the above-mentioned holding time can fully carbonize the carbon skeleton and form an orderly pore structure, while avoiding the collapse of pores and the decrease in specific surface area caused by excessive holding time. This allows the porous carbon material to have both excellent electrical conductivity, mechanical strength and stable pore structure.

[0042] In another specific embodiment, the protective atmosphere is an inert gas, preferably nitrogen. Of course, those skilled in the art can select different inert gases, such as helium and neon, based on factors such as reaction protection effect, thermal stability, and thermal conductivity.

[0043] In this embodiment, the porous carbon prepared by the above method has a micropore ratio of greater than or equal to 85% and a micropore volume of greater than or equal to 0.6 cm³. 3 / g, specific surface area greater than or equal to 1500m² 2 / g.

[0044] To verify the influence of the above preparation method and process parameters on the properties of porous carbon materials, this embodiment also set up four experimental groups and one control group to conduct a comparative experiment: In Experiment 1, high-sulfur asphalt with a sulfur content of 5% and a softening point of 50℃ was selected as the raw material. Then, 65g of high-sulfur asphalt, 15g of weakly acidic acrylic cation exchange resin, 5g of cyclohexanethiol and 15g of diphenyl sulfone were mixed to obtain a vulcanized crosslinked asphalt composite. Under a nitrogen atmosphere, the vulcanized crosslinked asphalt composite was heated to 130℃ and held for 4h to obtain vulcanized asphalt. Then, under a nitrogen atmosphere, the vulcanized asphalt was heated to 1400℃ and held for 3h to obtain porous carbon material.

[0045] In Experiment 2, high-sulfur asphalt with a sulfur content of 7% and a softening point of 60℃ was selected as the raw material. Then, 65g of high-sulfur asphalt, 15g of weakly acidic acrylic cation exchange resin, 5g of cyclohexanethiol and 15g of diphenyl sulfone were mixed to obtain a vulcanized crosslinked asphalt composite. Under a nitrogen atmosphere, the vulcanized crosslinked asphalt composite was heated to 130℃ and held for 4h to obtain vulcanized asphalt. Then, under a nitrogen atmosphere, the vulcanized asphalt was heated to 1400℃ and held for 3h to obtain porous carbon material.

[0046] In Experiment 3, high-sulfur asphalt with a sulfur content of 5% and a softening point of 50℃ was selected as the raw material. Then, 65g of high-sulfur asphalt, 15g of weakly acidic acrylic cation exchange resin, 5g of cyclohexanethiol, 5g of diphenyl sulfoxide, and 10g of diphenyl sulfone were mixed to obtain a vulcanized crosslinked asphalt composite. Under a nitrogen atmosphere, the vulcanized crosslinked asphalt composite was heated to 130℃ and held for 4h to obtain vulcanized asphalt. Then, under a nitrogen atmosphere, the vulcanized asphalt was heated to 1400℃ and held for 3h to obtain porous carbon material.

[0047] In Experiment 4, high-sulfur asphalt with a sulfur content of 5% and a softening point of 50℃ was selected as the raw material. Then, 60g of high-sulfur asphalt, 15g of weakly acidic acrylic cation exchange resin, 5g of cyclohexanethiol and 20g of diphenyl sulfone were mixed to obtain a vulcanized crosslinked asphalt composite. Under a nitrogen atmosphere, the vulcanized crosslinked asphalt composite was heated to 130℃ and held for 4h to obtain vulcanized asphalt. Then, under a nitrogen atmosphere, the vulcanized asphalt was heated to 1400℃ and held for 3h to obtain porous carbon material.

[0048] In the control group, 100g of polyvinyl alcohol (PVA) and 10g of ammonium sulfate were mixed evenly in water, and the mixture was vacuum dried at 80℃ to obtain a porous carbon precursor. The obtained porous carbon precursor was then heated to 750℃ in a box furnace under nitrogen gas protection at a rate of 5L / min and a heating rate of 10℃ / min, and held at that temperature for 10h to carbonize the porous carbon precursor. After natural cooling, the porous carbon material was finally removed from the box furnace to obtain a porous carbon material for silicon-carbon anode materials.

[0049] Please refer to Table 1, which shows the final specific surface area, micropore ratio, and pore volume of the porous carbon silicon-carbon anode materials prepared for experimental groups 1-4 and the control group.

[0050] Table 1 As shown in Table 1, the specific surface area, micropore ratio, and pore volume of the porous carbon prepared in experimental groups 1-4 are all larger than those of the porous carbon prepared in the control group.

[0051] It is evident that experimental groups 1-4 used low-cost high-sulfur asphalt as raw material, and by adding a small amount of ion exchange resin crosslinking agent, the high-sulfur asphalt was heat-treated to form a hard carbon structure. In addition, experimental groups 1-4 also added organic sulfides and controlled the type and amount of organic sulfides to regulate the specific surface area, micropore ratio and pore size distribution of porous carbon. Therefore, compared with the porous carbon prepared by polymer pyrolysis (prepared by the control group), it has a larger specific surface area and a richer pore structure.

[0052] Example 2 Based on the same inventive concept, this embodiment provides a negative electrode sheet, wherein the silicon-carbon negative electrode material used in the negative electrode sheet contains porous carbon prepared by the porous carbon preparation method for silicon-carbon negative electrode material disclosed in Example 1. The advantages of the porous carbon material disclosed in Example 1 are also present in the negative electrode sheet provided in this embodiment, and will not be repeated here.

[0053] In one specific embodiment, the preparation process of the above-mentioned negative electrode sheet is as follows: First, porous carbon material is prepared using the steps in Example 1. Then, nano-silicon is uniformly loaded onto the surface of the porous carbon material to form a silicon-carbon composite material. After that, the material is mixed with a conductive agent and a binder, and an appropriate amount of solvent is added to make a slurry. Finally, the slurry is uniformly coated on a copper foil, and after drying, rolling, cutting and other processes, a high-performance silicon-carbon negative electrode sheet can be obtained.

[0054] Example 3 Based on the same inventive concept, this embodiment discloses a lithium-ion battery, wherein the lithium-ion battery uses the negative electrode sheet disclosed in Embodiment 2. The advantages of the negative electrode sheet disclosed in Embodiment 2 are also present in the lithium-ion battery provided in this embodiment, and will not be repeated here.

[0055] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing porous carbon, characterized in that, The preparation method includes: High-sulfur asphalt, ion exchange resin crosslinking agent and organic sulfide are mixed to obtain sulfurized crosslinked asphalt composite; Under a protective atmosphere, the sulfurized crosslinked asphalt composite is subjected to a first heat treatment, which causes the organic sulfur compounds to undergo a crosslinking reaction with the high-sulfur asphalt to form sulfurized asphalt. Under a protective atmosphere, the sulfurized asphalt is subjected to a second heat treatment, which causes the sulfurized asphalt to carbonize and form a porous carbon material.

2. The method for preparing porous carbon as described in claim 1, characterized in that, The sulfur content in the high-sulfur asphalt is 4%-8%, and the softening point of the high-sulfur asphalt is 50-80°C. And / or, The first heat treatment includes: heating the vulcanized cross-linked asphalt composite to 120-160°C and holding it at that temperature for 3-5 hours; And / or, The second heat treatment includes heating the vulcanized asphalt to 1250-1450°C and holding it at that temperature for 2-4 hours.

3. The method for preparing porous carbon as described in claim 1, characterized in that, The ion exchange resin crosslinking agent includes at least one of cation exchange resin and anion exchange resin.

4. The method for preparing porous carbon as described in claim 3, characterized in that, The cation exchange resin includes at least one of a strong acid styrene cation exchange resin and a weak acid acrylic cation exchange resin; the anion exchange resin includes a weak acid acrylic anion exchange resin.

5. The method for preparing porous carbon as described in claim 1, characterized in that, The organic sulfides include at least one of thiols, sulfoxides, and sulfones.

6. The method for preparing porous carbon as described in claim 5, characterized in that, The thiol is ethanethiol, butanethiol, or cyclohexanethiol; the sulfoxide is dimethyl sulfoxide, diethyl sulfoxide, cyclobutane sulfoxide, or diphenyl sulfoxide; the sulfone is diethyl sulfone, cyclobutane sulfone, or diphenyl sulfone.

7. The method for preparing porous carbon according to any one of claims 1-6, characterized in that, In the vulcanized crosslinked asphalt composite, the high-sulfur asphalt accounts for 60%-70% by mass, the ion exchange resin crosslinking agent accounts for 10%-15% by mass, and the organic sulfide accounts for 15%-25% by mass.

8. A porous carbon, characterized in that, The porous carbon is prepared by the method described in any one of claims 1-7, wherein the micropore ratio of the porous carbon is greater than or equal to 85%, and the micropore volume is greater than or equal to 0.6 cm³. 3 / g, specific surface area greater than or equal to 1500m² 2 / g.

9. A negative electrode sheet, characterized in that, The negative electrode sheet includes porous carbon as described in claim 8.

10. A lithium-ion battery, characterized in that, The lithium-ion battery includes the negative electrode sheet as described in claim 9.

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