A non-metallic porous carbon anode material, its preparation method and application

Abstract

This invention relates to a non-metallic porous carbon anode material, its preparation method, and its application. The preparation method includes: activating a carbon-containing raw material in a hydrogen-containing mixed gas to obtain porous carbon and a benzene-rich hydrocarbon gas; depositing the non-metallic source gas and the porous carbon in a primary deposition; and then depositing the non-metallic source gas and the benzene-rich hydrocarbon gas in a secondary deposition to obtain the non-metallic porous carbon anode material. The carbon-containing raw material is further de-ashed before use, or the porous carbon is de-ashed and then mixed. This invention achieves continuous preparation of porous carbon and non-metallic porous carbon anode materials by activating the carbon-containing raw material with hydrogen. The excess hydrogen generated in this process can be recycled to the hydrogen activation step for reuse. Hydrogen activation enables efficient deoxygenation of the carbon-containing material, avoiding the generation of other oxide impurities during the deposition of non-metals, effectively ensuring the safety of the deposition process. The benzene-rich hydrocarbon byproduct generated during the preparation of porous carbon can further carbonize the material, achieving efficient utilization of carbon resources.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a non-metallic porous carbon anode material, its preparation method, and its application. Background Technology

[0002] With the emphasis on environmental protection and dual-carbon goals, my country's requirements for the efficient conversion and utilization of traditional fossil energy and new energy technologies are increasingly stringent. my country possesses abundant carbon-containing resources such as coal and biomass, but the primary method of utilizing these resources is direct combustion, resulting in significant waste of these valuable resources. Coal, biomass, and petroleum coke are the main raw materials for preparing porous carbon. Given the high added value of battery-grade porous carbon materials, the use of these raw materials to prepare porous carbon has enormous application potential.

[0003] Porous carbon, as a negative electrode for lithium-ion batteries, has a theoretical capacity of only 372 mAh / g. However, by depositing silicon (theoretical capacity 4200 mAh / g) or phosphorus (theoretical capacity 2596 mAh / g) into porous carbon, the prepared silicon-carbon or phosphorus-carbon negative electrode materials can greatly improve the lithium storage performance of porous carbon. However, silicon or phosphorus as negative electrode materials have the problem of high expansion rate and easy breakage. Therefore, by depositing silicon or phosphorus into porous carbon, the porous carbon can act as a volume expansion buffer, which can further improve the stability of silicon or phosphorus and achieve high capacity and high stability lithium storage performance.

[0004] Phosphorus's layered structure and good conductivity make it a promising material for development in alkali metal ion batteries such as sodium-ion batteries. As a negative electrode material for sodium-ion batteries, phosphorus has a theoretical specific capacity of up to 2596 mAh / g. Therefore, phosphorus-based hard carbon obtained by depositing phosphorus in porous carbon can also serve as an excellent material for improving the capacity and stability of alkali metal ion batteries such as sodium-ion batteries.

[0005] Currently, the main method for preparing porous carbon materials that act as buffers is under an inert atmosphere (Ar, N2), using metal compounds such as ZnCl2 and KOH as activators and pore-forming agents. This process is costly, generates metal vapors and HCl, polluting the environment, and the residues require further cleaning. Alternatively, CO or CO2 can be used as pore-forming agents, but the effect is still limited and cannot achieve deep deoxygenation. This can adversely affect the deposition of non-metallic materials in the subsequent preparation of anode materials. In addition, the process of preparing porous carbon from coal releases a large amount of organic matter in gaseous form, resulting in resource waste. The traditional method of using hydrogen-assisted reduction of coal to prepare oil and hydrocarbon products also produces a large amount of semi-coke byproducts, resulting in resource waste.

[0006] CN113307267A discloses a method for preparing coal-based porous carbon using alkali metal compounds such as KOH and NaOH as pore-forming agents. This process has a short route and fast production speed, but the method is costly and the generated alkali metal vapors pollute the environment. In addition, the porous carbon obtained by adding metal compounds cannot remove oxygen and retains a large number of oxygen defects. If silicon deposition is to be performed, it will cause silicon combustion and lead to the formation of silicon dioxide.

[0007] CN114890420A discloses a method for preparing coal-based porous carbon. The porous carbon prepared by this method has a hierarchical pore structure of micropores and mesopores. The porous carbon material prepared by this method has a high specific capacity, but the overall process route is long and the preparation process requires high-energy ball milling, addition of raw materials such as acids and alkalis, which causes significant environmental pollution.

[0008] CN115491221A discloses a method for preparing oil hydrocarbons by hydrogenating coal under high pressure. Coal hydrogenation liquefaction methods, represented by this process, generally produce semi-coke, which accounts for about 50% of the raw material mass, resulting in serious resource waste.

[0009] Therefore, how to improve the high cost, environmental pollution, and waste of hydrocarbons in the raw materials during the preparation of porous carbon from carbon-containing natural resources, and how to achieve the continuous preparation of efficient and low-cost non-metallic porous carbon anode materials are the technical problems that urgently need to be solved. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a non-metallic porous carbon anode material, its preparation method, and its application. By activating carbon-containing raw materials with hydrogen, the continuous preparation of porous carbon and non-metallic porous carbon anode materials is achieved. Excess hydrogen generated during this process can be recycled back to the hydrogen activation step for reuse. Hydrogen activation enables efficient deoxygenation of the carbon-containing material, avoiding the generation of other non-metallic oxide impurities during non-metal deposition. The benzene-rich hydrocarbon byproducts generated during the activation preparation of porous carbon can further carbonize the material, thereby achieving efficient utilization of carbon resources.

[0011] To achieve this objective, the present invention adopts the following technical solution:

[0012] In a first aspect, the present invention provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0013] (1) Activate the carbon-containing raw material in a hydrogen-containing mixed gas to obtain porous carbon and benzene-rich hydrocarbon gas;

[0014] (2) Mix the non-metallic source gas with the porous carbon described in step (1) and perform a first deposition. Mix the obtained first deposition product with the benzene-rich hydrocarbon gas described in step (1) and perform a second deposition to obtain a non-metallic porous carbon anode material.

[0015] Wherein, the benzene-rich hydrocarbon gas in step (1) includes any one or a combination of at least two of alkanes, aromatic hydrocarbons, alkenes or alkynes;

[0016] The carbon-containing raw material in step (1) may also be deashed before use, or the porous carbon in step (1) may be deashed before step (2).

[0017] This invention activates carbon-containing resources after deashing and purification using hydrogen. At the same time, hydrogen also acts as a pore-forming agent, realizing the synergistic production of porous carbon and benzene-rich hydrocarbons. In addition, the presence of hydrogen can also achieve efficient deoxygenation, avoiding safety issues caused by high oxygen content during the deposition of non-metals, and also preventing the generation of other non-metallic oxide impurities during the process.

[0018] This invention uses porous carbon and benzene-rich hydrocarbon gas as raw materials to prepare non-metallic porous carbon anode materials. The porous carbon has a high specific surface area and can serve as a buffer substrate for the anode material. Non-metals with high expansion rates, such as silicon, phosphorus, or carbon, are deposited inside the porous carbon channels, providing space for expansion and greatly alleviating the problem of high expansion rates in anode materials. At the same time, the porous structure ensures the rapid passage of lithium ions. In addition, the generated benzene-rich hydrocarbon gas byproduct can be used as a raw material for carbon coating, making full use of the carbon-containing raw materials. The presence of the carbon coating layer further plays a buffering role, improving the overall conductivity of the material. The resulting non-metallic porous carbon anode material has high specific capacity and excellent cycle performance.

[0019] As a preferred technical solution of the present invention, the carbon-containing raw material in step (1) includes any one or a combination of at least two of coal, biomass, asphalt or petroleum coke.

[0020] Preferably, the coal includes medium- and low-rank coal.

[0021] Preferably, the medium- and low-rank coal includes any one or a combination of at least two of bituminous coal, sub-bituminous coal, or lignite.

[0022] It should be noted that the bituminous coal used in this invention is low volatile bituminous coal. According to GB5751-86 "Classification of Chinese Coal", the volatile content of low volatile bituminous coal is in the range of 10% to 20%.

[0023] Preferably, the alkane includes any one or a combination of at least two of methane, ethane, or propane.

[0024] Preferably, the aromatic hydrocarbon includes any one or a combination of at least two of benzene, naphthalene, phenanthrene, pyrene, toluene, or ethylbenzene.

[0025] Preferably, the olefin includes propylene or ethylene.

[0026] Preferably, the alkyne includes acetylene.

[0027] It should be noted that, based on the specific type of carbon raw material, the specific types of benzene-rich hydrocarbon gas can be adaptively adjusted.

[0028] Preferably, the hydrogen-containing mixed gas in step (1) includes a mixture of hydrogen and argon.

[0029] Preferably, in the mixture of hydrogen and argon, the hydrogen content is 0 to 5 vol%, and is not 0, for example, 1 vol%, 2 vol%, 3 vol%, 4 vol%, or 5 vol%.

[0030] Preferably, the deashing includes mechanical deashing or chemical deashing.

[0031] In this invention, deashing can achieve the purification of carbon-containing raw materials.

[0032] As a preferred technical solution of the present invention, the activation temperature in step (1) is 700 to 1000°C, such as 700°C, 720°C, 750°C, 780°C, 800°C, 820°C, 850°C, 880°C, 900°C, 920°C, 950°C, 980°C or 1000°C.

[0033] In this invention, if the activation temperature of hydrogen activation is too high, the porous carbon structure will collapse and fail to play a buffering role, and the generation of benzene-rich hydrocarbon gas will also decrease, resulting in a waste of resources; if the activation temperature of hydrogen activation is too low, pore formation will not be achieved, or the pore size after pore formation will be too small, the proportion of micropores will be too high, and it will be difficult to deposit non-metals.

[0034] Preferably, the heating rate for activation in step (1) is 0.05 to 15 °C / min, for example, 0.05 °C / min, 0.1 °C / min, 0.5 °C / min, 1 °C / min, 3 °C / min, 5 °C / min, 8 °C / min, 10 °C / min, 12 °C / min or 15 °C / min.

[0035] Preferably, the activation holding time in step (1) is 1 to 5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours or 5 hours.

[0036] Preferably, the activation pressure in step (1) is 0.1 to 10 MPa, for example, 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa or 10 MPa.

[0037] In this invention, by adjusting the activation temperature, activation pressure and heating rate of hydrogen activation, the synergistic production of porous carbon and benzene-rich hydrocarbon gas is achieved, providing a high-performance raw material for the preparation of non-metallic porous carbon anode materials.

[0038] Preferably, the flow rate of the hydrogen and argon mixture in step (1) is 100-500 mL / min, for example, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min, 400 mL / min, 450 mL / min or 500 mL / min.

[0039] As a preferred technical solution of the present invention, the non-metallic source gas in step (2) includes any one of silane, phosphorus vapor, phosphine, phosphorus bromide, triphenylphosphine or alkanes.

[0040] Preferably, the alkane includes any one or a combination of at least two of methane, ethane, propane, or butane.

[0041] Preferably, the deposition method in step (2) includes vapor phase deposition.

[0042] Preferably, the temperature of the first deposition in step (2) is 300 to 800°C, such as 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C.

[0043] Preferably, the secondary deposition method in step (2) includes vapor phase deposition.

[0044] Preferably, the temperature of the secondary deposition in step (2) is 300 to 1000°C, such as 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, or 1000°C.

[0045] Preferably, after the secondary deposition in step (2), drying is also included.

[0046] Preferably, the drying temperature is 60 to 200°C, such as 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, or 200°C.

[0047] Preferably, the drying time is 5 to 12 hours, such as 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.

[0048] As a preferred embodiment of the present invention, the preparation method includes the following steps:

[0049] (1) The carbon-containing raw material after deashing is activated in a mixture of hydrogen and argon at a rate of 0.05-15℃ / min to 700-1000℃, and kept at the temperature for 1-5 hours. The activation pressure is 0.1-10 MPa to obtain porous carbon and benzene-rich hydrocarbon gas.

[0050] The hydrogen and argon mixture contains 0-5 vol% hydrogen, and is not zero; the flow rate of the hydrogen and argon mixture is 100-500 mL / min; the carbon-containing raw material includes any one or at least two of coal, biomass, bituminous coal, or petroleum coke; the deashing includes mechanical deashing or chemical deashing; the coal includes medium- and low-rank coal; the medium- and low-rank coal includes any one or at least two of bituminous coal, sub-bituminous coal, or lignite; the benzene-rich hydrocarbon gas includes any one or at least two of alkanes, aromatic hydrocarbons, alkenes, or alkynes; the alkanes include any one or at least two of methane, ethane, or propane; the aromatic hydrocarbons include any one or at least two of benzene, naphthalene, phenanthrene, pyrene, toluene, or ethylbenzene; the olefins include propylene or ethylene; and the alkynes include acetylene.

[0051] (2) The non-metallic source gas and the porous carbon described in step (1) are deposited once by vapor deposition at 300-800°C. The obtained primary deposition product is deposited twice by vapor deposition at 300-1000°C with the benzene-rich hydrocarbon gas described in step (1). The obtained product is dried at 60-200°C for 5-12 hours to obtain a non-metallic porous carbon anode material.

[0052] The non-metallic source gas includes any one of silane, phosphorus vapor, phosphine, phosphorus bromide, triphenylphosphine, or alkanes; the alkanes include any one or a combination of at least two of methane, ethane, propane, or butane.

[0053] In a second aspect, the present invention also provides a non-metallic porous carbon anode material, which is prepared according to the preparation method described in the first aspect.

[0054] As a preferred technical solution of the present invention, the non-metallic porous carbon material includes silicon-carbon anode material, phosphorus-carbon anode material or carbon / carbon composite anode material.

[0055] As a preferred embodiment of the present invention, the silicon-carbon anode material comprises porous carbon, silicon particles dispersed in the pores of the porous carbon, and a carbon coating layer covering the surface of the porous carbon.

[0056] Preferably, the phosphorus-carbon anode material comprises porous carbon, phosphorus particles dispersed in the pores of the porous carbon, and a carbon coating layer covering the surface of the porous carbon.

[0057] Preferably, the carbon / carbon composite anode material comprises porous carbon, carbon particles dispersed in the pores of the porous carbon, and a carbon coating layer covering the surface of the porous carbon.

[0058] Thirdly, the present invention also provides an application of a non-metallic porous carbon anode material, wherein the non-metallic porous carbon anode material prepared by the preparation method described in the first aspect, or the non-metallic porous carbon anode material described in the second aspect, is applied to a sodium-ion battery.

[0059] Fourthly, the present invention also provides an application of a non-metallic porous carbon anode material, wherein the non-metallic porous carbon anode material prepared by the preparation method described in the first aspect, or the non-metallic porous carbon anode material described in the second aspect, is mixed with graphite and applied to a lithium-ion battery.

[0060] Preferably, the graphite includes natural graphite or artificial graphite.

[0061] Preferably, the mass ratio of the graphite to the non-metallic porous carbon anode material is (0.05 to 10):1, for example, 0.05:1, 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc.

[0062] Compared with the prior art, the present invention has at least the following beneficial effects:

[0063] 1) This invention utilizes hydrogen to activate the pyrolysis of carbon-containing raw materials to achieve continuous preparation of porous carbon and non-metallic porous carbon anode materials. Hydrogen is used as a pore-forming agent, and the steam generated when the carbon-containing raw materials decompose at high temperature can also be used as a pore-forming agent to be generated from inside the carbon-containing raw material skeleton. The excess hydrogen generated in this process can be recovered into a mixture of hydrogen and argon and used again to activate the carbon-containing raw materials, thus achieving recycling.

[0064] 2) The porous carbon prepared by this invention has a uniform internal pore size distribution and a large specific surface area. At the same time, the oxygen can be efficiently removed by hydrogen activation, which is beneficial to the subsequent deposition of non-metals and avoids the safety problems caused by high oxygen content during the deposition of non-metals. It also avoids the generation of other non-metal oxide impurities during the process.

[0065] 3) The gaseous benzene-rich hydrocarbon byproducts generated during the preparation of porous carbon in this invention can be used as coating raw materials to coat materials, thereby achieving efficient utilization of carbon-containing raw materials and near-zero emissions of pollutants. This avoids the need to use traditional raw materials such as acetylene for coating. The process is simple, easy to implement, and can be scaled up for production. Attached Figure Description

[0066] Figure 1 This is a process flow diagram of the preparation of non-metallic porous carbon anode material in Embodiment 1 of the present invention;

[0067] Figure 2 This is a BET adsorption-desorption curve of the negative electrode powder prepared in Example 1 of this invention;

[0068] Figure 3 This is a graph showing the first charge-discharge curve of the lithium-ion battery prepared using Example 1 of this invention.

[0069] Figure 4 This is a graph showing the first charge-discharge curve of the sodium-ion battery prepared in Example 12 of this invention. Detailed Implementation

[0070] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0071] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0072] Example 1

[0073] This embodiment provides a method for preparing a non-metallic porous carbon anode material, and the process flow diagram of the non-metallic porous carbon anode material is shown below. Figure 1 As shown, the preparation method includes the following steps:

[0074] (1) Bituminous coal with a particle size of less than 74 μm was washed with hydrochloric acid and hydrofluoric acid and then placed in a high-temperature tube furnace. A mixed gas containing 5 vol% hydrogen and argon was introduced at a flow rate of 500 mL / min. The temperature was raised to 800 °C at a heating rate of 0.05 °C / min and held at the target temperature for 2 h at a pressure of 2 MPa. The gas was then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0075] (2) The porous carbon was deposited with silane at 500°C by vapor deposition. Then, the obtained primary deposition product was deposited with benzene-rich hydrocarbon gas at 500°C by vapor deposition. The product was dried at 120°C for 8 hours and cooled to room temperature to obtain silicon-carbon anode material.

[0076] Example 2

[0077] This embodiment provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0078] (1) Bituminous coal with a particle size of less than 74 μm was placed into a high-temperature tubular furnace, and a mixed gas containing 5 vol% hydrogen and argon was introduced at a flow rate of 300 mL / min. The temperature was raised to 800 °C at a heating rate of 0.05 °C / min, and held at the target temperature for 2 h at a pressure of 2 MPa. The gas was then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0079] (2) After washing the porous carbon with hydrochloric acid and hydrofluoric acid, the deashed porous carbon is deposited with silane at 500°C by vapor deposition. Then, the obtained primary deposition product is deposited with benzene-rich hydrocarbon gas at 500°C by vapor deposition. After drying at 60°C for 12 hours, it is cooled to room temperature to obtain silicon-carbon anode material.

[0080] Example 3

[0081] This embodiment provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0082] (1) Bituminous coal with a particle size of less than 74 μm was washed with hydrochloric acid and hydrofluoric acid and then placed in a high-temperature tube furnace. A mixed gas containing 5 vol% hydrogen and argon was introduced at a flow rate of 500 mL / min. The temperature was raised to 700 °C at a heating rate of 0.05 °C / min. The temperature was held at the target temperature for 2 h at a pressure of 5 MPa and then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0083] (2) The porous carbon was deposited with silane at 500°C by vapor deposition. Then, the primary deposited product was deposited with benzene-rich hydrocarbon gas at 500°C by vapor deposition. The product was dried at 200°C for 5 hours and cooled to room temperature to obtain silicon-carbon anode material.

[0084] Example 4

[0085] This embodiment provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0086] (1) Bituminous coal with a particle size of less than 74 μm was washed with hydrochloric acid and hydrofluoric acid and then placed in a high-temperature tube furnace. A mixed gas containing 5 vol% hydrogen and argon was introduced at a flow rate of 500 mL / min. The temperature was raised to 1000 °C at a heating rate of 0.05 °C / min and held at the target temperature for 2 h at a pressure of 5 MPa. The gas was then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0087] (2) The porous carbon was deposited with silane at 400°C by vapor deposition. Then, the primary deposited product was deposited with benzene-rich hydrocarbon gas at 800°C by vapor deposition. The product was dried at 180°C for 10 hours and cooled to room temperature to obtain silicon-carbon anode material.

[0088] Example 5

[0089] This embodiment provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0090] (1) After washing walnut shells with a particle size of less than 74 μm with hydrochloric acid and hydrofluoric acid, they were placed in a high-temperature tube furnace and a mixed gas containing 3 vol% hydrogen and argon was introduced at a flow rate of 500 mL / min. The temperature was raised to 900 °C at a heating rate of 0.05 °C / min, and held at the target temperature for 2 h at a pressure of 2 MPa. The mixture was then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0091] (2) The porous carbon was deposited with silane at 420°C by vapor deposition. Then, the primary deposited product was deposited with benzene-rich hydrocarbon gas at 800°C by vapor deposition. The product was dried at 100°C for 9 hours and cooled to room temperature to obtain silicon-carbon anode material.

[0092] Example 6

[0093] This embodiment provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0094] (1) Asphalt with a particle size of less than 74 μm was placed into a high-temperature tube furnace and a mixed gas containing 2 vol% hydrogen and argon was introduced at a flow rate of 100 mL / min. The temperature was raised to 1000 °C at a heating rate of 15 °C / min, and held at the target temperature for 1 h at a pressure of 10 MPa. The gas was then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0095] (2) After washing the porous carbon with hydrochloric acid and hydrofluoric acid, the porous carbon is deposited with silane at 450°C by vapor deposition. Then, the obtained primary deposition product is deposited with benzene-rich hydrocarbon gas at 900°C by vapor deposition. After drying at 150°C for 11 hours, it is cooled to room temperature to obtain silicon-carbon anode material.

[0096] Example 7

[0097] This embodiment provides a method for preparing a non-metallic porous carbon anode material. The difference between the preparation method and that in Example 1 is that in step (2), phosphine is used to deposit porous carbon. The remaining preparation methods and parameters are consistent with those in Example 1, and the prepared material is a phosphorus-carbon anode material.

[0098] Example 8

[0099] This embodiment provides a method for preparing a non-metallic porous carbon anode material. The difference between this method and that of Example 1 is that in step (1), the activation temperature is 600°C, while the rest of the preparation methods and parameters remain the same as those of Example 1.

[0100] Example 9

[0101] This embodiment provides a method for preparing a non-metallic porous carbon anode material. The difference between this method and that of Example 1 is that in step (1), the activation temperature is 1100℃, while the rest of the preparation methods and parameters are consistent with those of Example 1.

[0102] Example 10

[0103] This embodiment provides a method for preparing a non-metallic porous carbon anode material, the method comprising the following steps:

[0104] (1) After washing walnut shells with a particle size of less than 74 μm with hydrochloric acid and hydrofluoric acid, they were placed in a high-temperature tube furnace and a mixed gas containing 3 vol% hydrogen and argon was introduced at a flow rate of 500 mL / min. The temperature was raised to 900 °C at a heating rate of 0.05 °C / min, and held at the target temperature for 2 h at a pressure of 2 MPa. The mixture was then naturally cooled to room temperature to obtain porous carbon and benzene-rich hydrocarbon gas. The excess hydrogen was returned to the mixed gas.

[0105] (2) The porous carbon was deposited with acetylene at 450°C by vapor deposition. Then, the primary deposited product was deposited with benzene-rich hydrocarbon gas at 1000°C by vapor deposition. The carbon / carbon composite anode material was obtained by drying at 80°C for 12 hours and cooling to room temperature.

[0106] Comparative Example 1

[0107] This comparative example provides a method for preparing a non-metallic porous carbon anode material. The difference between this method and Example 1 is that in step (1), bituminous coal is activated in nitrogen, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0108] Comparative Example 2

[0109] This comparative example provides a method for preparing a non-metallic porous carbon anode material. The difference between this method and Example 1 is that the step of deashing bituminous coal is omitted, while the rest of the preparation method and parameters remain the same as in Example 1.

[0110] Application Examples 1-9 and Comparative Application Examples 1-2

[0111] The non-metallic porous carbon anode materials prepared in Examples 1-9 and Comparative Examples 1-2 were mixed with graphite to obtain anode powder, and then anode sheets were prepared. Lithium sheets were used as cathode sheets, and EC+DMC was used as electrolyte. Lithium-ion batteries were assembled, corresponding to Application Examples 1-9 and Comparative Application Examples 1-2, respectively.

[0112] Application Example 10

[0113] The non-metallic porous carbon anode material prepared in Example 1 was used to prepare an anode sheet. A sodium sheet was used as the positive electrode sheet, and DME was used as the electrolyte to assemble a sodium-ion battery.

[0114] Application Example 11

[0115] The non-metallic porous carbon anode material prepared in Example 7 was used to prepare an anode sheet. A sodium sheet was used as the positive electrode sheet, and DME was used as the electrolyte to assemble a sodium-ion battery.

[0116] Application Example 12

[0117] The non-metallic porous carbon anode material prepared in Example 10 was used to prepare an anode sheet. A sodium sheet was used as the positive electrode sheet, and DME was used as the electrolyte to assemble a sodium-ion battery.

[0118] Test methods

[0119] 1) The porous carbon prepared in step (1) of Examples 1-10 and Comparative Examples 1-2 was tested for specific surface area using a nitrogen physical adsorption-desorption instrument. The specific test results are shown in Table 1.

[0120] 2) The specific surface area of ​​the negative electrode powders prepared in Application Examples 1-9 and Application Examples 1-2 was tested using a nitrogen physical adsorption-desorption instrument. The specific test results are shown in Table 2.

[0121] 3) The lithium-ion batteries prepared in Application Examples 1 to 9 and Application Examples 1 to 2 were charged and discharged at a rate of 1C within a voltage range of 2.5 to 4.2V. The specific test results are shown in Table 2.

[0122] 4) The non-metallic porous carbon anode materials prepared in Examples 1, 7 and 10 were subjected to specific surface area testing using a nitrogen physical adsorption-desorption instrument. The specific test results are shown in Table 3.

[0123] 5) The sodium-ion batteries prepared in Application Examples 10-12 were charged and discharged at a rate of 1C within a voltage range of 2.5-4.2V. The specific test results are shown in Table 3.

[0124] Figure 2 The BET adsorption-desorption curves of the negative electrode powder prepared in Application Example 1 are shown. As can be seen from the figure, the specific surface area of ​​the negative electrode powder reaches 16.6 m². 2 / g.

[0125] Figure 3 The first charge-discharge curve of the lithium-ion battery prepared in Application Example 1 is shown. As can be seen from the figure, the charging specific capacity can reach 558 mAh / g.

[0126] Table 1

[0127] project <![CDATA[Specific surface area of porous carbon (m 2 / g)]]> Example 1 251.5 Example 2 252.4 Example 3 248.8 Example 4 250.6 Example 5 251 Example 6 287.8 Example 7 252.1 Example 8 222.9 Example 9 223.2 Example 10 260.0 Comparative Example 1 201.6 Comparative Example 2 220

[0128] Table 2

[0129]

[0130] Figure 4 The first charge-discharge curve of the sodium-ion battery prepared in Application Example 12 is shown. As can be seen from the figure, the specific charge capacity can reach 360 mAh / g.

[0131] Table 3

[0132]

[0133] The test results show that:

[0134] (1) As can be seen from Examples 1 to 10 in Table 1 and Application Examples 1 to 9 in Table 2, the present invention activates carbon-containing raw materials with hydrogen to obtain porous carbon and benzene-rich hydrocarbon gas. Subsequently, the porous carbon is used as a carrier for silicon particle deposition, phosphorus particle deposition, or carbon particle deposition, allowing the particles to enter the channels of the porous carbon. The presence of porous carbon provides space for the volume expansion of silicon, phosphorus, and carbon during battery operation, alleviating the problem of negative electrode volume expansion. In addition, the benzene-rich hydrocarbon gas is used as a byproduct as a raw material for carbon coating, making full use of the byproduct. The presence of the carbon coating layer also plays a buffering role, improving the overall conductivity of the material. Specifically, the specific surface area of ​​the prepared porous carbon is 222 m². 2 The specific capacity of the lithium-ion batteries assembled from the negative electrode powder is above 440mAh / g, and the initial capacity retention rate is above 90%.

[0135] (2) As can be seen from Examples 1 and 8-9 in Table 1 and Application Examples 1 and 8-9 in Table 2, by further controlling the activation temperature to 700-1000℃, the present invention can better achieve the effect of hydrogen activation, and the prepared porous carbon has a higher specific surface area. The specific capacity and initial capacity retention rate of the negative electrode material obtained after two depositions are both better.

[0136] (3) As can be seen from Example 1 and Comparative Example 1 in Table 1, the present invention can only prepare a negative electrode material with better performance by activating it in hydrogen. At the same time, hydrogen also acts as a pore-forming agent, realizing the synergistic production of porous carbon and benzene-rich hydrocarbon gas. In addition, the presence of hydrogen can also achieve efficient deoxygenation, avoiding the safety problems caused by high oxygen content during the deposition of non-metals, and also avoiding the generation of other non-metal oxide impurities in the process. Nitrogen does not play the role that hydrogen can.

[0137] (4) As can be seen from Example 1 and Comparative Example 2 in Table 1, and Application Example 1 and Comparative Application Example 2 in Table 2, when the deashing and purification step is omitted in this invention, the impurities inside the carbon-containing raw material will affect conductivity, ion transport and mass activity, thereby reducing the specific surface area of ​​porous carbon and affecting the specific capacity and initial capacity retention rate of the anode material.

[0138] (5) As can be seen from the application examples 10-12 in Table 3, the silicon-carbon anode material, phosphorus-carbon anode material and carbon / carbon anode material prepared in this invention all exhibit high anode specific capacity and initial capacity retention rate after being assembled into sodium-ion batteries, and also have superior electrochemical performance when applied in sodium-ion batteries.

[0139] In summary, this invention enables the continuous preparation of porous carbon and non-metallic porous carbon anode materials through hydrogen activation of carbon-containing raw materials. Hydrogen activation efficiently deoxygenates the carbon-containing materials, avoiding the generation of other non-metallic oxide impurities during non-metal deposition. Excess hydrogen generated during activation can be recycled back to the hydrogen activation step for reuse. Furthermore, the benzene-rich hydrocarbon byproducts generated during hydrogen activation of carbon-containing materials can be further used for carbon coating, thereby achieving efficient utilization of carbon resources.

[0140] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a non-metallic porous carbon anode material, characterized in that, The preparation method includes the following steps: (1) Activate the carbon-containing raw material in a hydrogen-containing mixed gas to obtain porous carbon and benzene-rich hydrocarbon gas; (2) Mix the non-metallic source gas with the porous carbon described in step (1) and perform a first deposition. Mix the obtained first deposition product with the benzene-rich hydrocarbon gas described in step (1) and perform a second deposition to obtain a non-metallic porous carbon anode material. Wherein, the benzene-rich hydrocarbon gas in step (1) includes any one or a combination of at least two of alkanes, aromatic hydrocarbons, alkenes or alkynes; The carbon-containing raw material in step (1) may also be deashed before use, or the porous carbon in step (1) may be deashed before step (2). The hydrogen-containing mixed gas in step (1) includes a mixture of hydrogen and argon; The hydrogen and argon mixture contains 0 to 5 vol% hydrogen, and is not zero. The activation temperature in step (1) is 700~1000℃; The non-metallic source gas in step (2) includes any one of phosphorus vapor, phosphine, phosphorus bromide, triphenylphosphine, or alkanes; The primary deposition method in step (2) includes vapor phase deposition; The secondary deposition method in step (2) includes vapor phase deposition.

2. The preparation method according to claim 1, characterized in that, The carbon-containing raw materials in step (1) include any one or a combination of at least two of coal, biomass, asphalt, or petroleum coke.

3. The preparation method according to claim 2, characterized in that, The coal includes medium and low rank coal.

4. The preparation method according to claim 3, characterized in that, The medium- and low-rank coals include any one or a combination of at least two of bituminous coal, sub-bituminous coal, or lignite.

5. The preparation method according to claim 1, characterized in that, The alkanes in the benzene-rich hydrocarbon gas include any one or a combination of at least two of methane, ethane, or propane.

6. The preparation method according to claim 1, characterized in that, The aromatic hydrocarbon includes any one or a combination of at least two of benzene, naphthalene, phenanthrene, pyrene, toluene, or ethylbenzene.

7. The preparation method according to claim 1, characterized in that, The olefins include propylene or ethylene.

8. The preparation method according to claim 1, characterized in that, The alkynes include acetylene.

9. The preparation method according to claim 1, characterized in that, The deashing includes mechanical deashing or chemical deashing.

10. The preparation method according to claim 1, characterized in that, The heating rate for activation in step (1) is 0.05~15℃ / min.

11. The preparation method according to claim 1, characterized in that, The activation holding time in step (1) is 1~5h.

12. The preparation method according to claim 1, characterized in that, The activation pressure in step (1) is 0.1~10 MPa.

13. The preparation method according to claim 1, characterized in that, The alkane in the non-metallic source gas includes any one or a combination of at least two of methane, ethane, propane, or butane.

14. The preparation method according to claim 1, characterized in that, The temperature of the first deposition in step (2) is 300~800℃.

15. The preparation method according to claim 1, characterized in that, The temperature of the secondary deposition in step (2) is 300~1000℃.

16. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) The carbon-containing raw material after deashing is activated in a mixture of hydrogen and argon at a rate of 0.05~15℃ / min to 700~1000℃, kept at the temperature for 1~5h, and activated at an activation pressure of 0.1~10MPa to obtain porous carbon and benzene-rich hydrocarbon gas. The hydrogen and argon mixture contains 0-5 vol% hydrogen, and is not zero; the flow rate of the hydrogen and argon mixture is 100-500 mL / min; the carbon-containing raw material includes any one or a combination of at least two of coal, biomass, bitumen, or petroleum coke; the deashing includes mechanical deashing or chemical deashing; the coal includes medium- and low-rank coal; the medium- and low-rank coal includes any one or a combination of at least two of bituminous coal, sub-bituminous coal, or lignite; the benzene-rich hydrocarbon gas includes any one or a combination of at least two of alkanes, aromatic hydrocarbons, alkenes, or alkynes; the alkanes include any one or a combination of at least two of methane, ethane, or propane; the aromatic hydrocarbons include any one or a combination of at least two of benzene, naphthalene, phenanthrene, pyrene, toluene, or ethylbenzene; the olefins include propylene or ethylene; and the alkynes include acetylene. (2) The non-metallic source gas and the porous carbon described in step (1) are deposited once by vapor deposition at 300~800℃. The obtained primary deposition product is deposited a second time with the benzene-rich hydrocarbon gas described in step (1) by vapor deposition at 300~1000℃. The obtained product is dried at 60~200℃ for 5~12h to obtain a non-metallic porous carbon anode material. The non-metallic source gas includes any one of phosphorus vapor, phosphine, phosphorus bromide, triphenylphosphine, or alkanes; the alkanes include any one or a combination of at least two of methane, ethane, propane, or butane.

17. A non-metallic porous carbon anode material, characterized in that, The non-metallic porous carbon anode material is prepared by the preparation method according to any one of claims 1-16.

18. The non-metallic porous carbon anode material according to claim 17, characterized in that, The non-metallic porous carbon anode material includes phosphorus-carbon anode material or carbon / carbon composite anode material.

19. The non-metallic porous carbon anode material according to claim 18, characterized in that, The phosphorus-carbon anode material includes porous carbon, phosphorus particles dispersed in the pores of the porous carbon, and a carbon coating layer covering the surface of the porous carbon.

20. The non-metallic porous carbon anode material according to claim 18, characterized in that, The carbon / carbon composite anode material includes porous carbon, carbon particles dispersed in the pores of the porous carbon, and a carbon coating layer covering the surface of the porous carbon.

21. An application of a non-metallic porous carbon anode material, characterized in that, The non-metallic porous carbon anode material prepared by the preparation method according to any one of claims 1-16, or the non-metallic porous carbon anode material according to any one of claims 17-20, is applied to a sodium-ion battery.

22. An application of a non-metallic porous carbon anode material, characterized in that, The non-metallic porous carbon anode material prepared by the preparation method according to any one of claims 1-16, or the non-metallic porous carbon anode material according to any one of claims 17-20, after being mixed with graphite, is applied to a lithium-ion battery.

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