Preparation method of coal-based porous carbon material and application thereof
Patent Information
- Application Number
- CN202611085258.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-21
- Publication Date
- 2026-08-18
AI Technical Summary
然而，以KOH为代表的传统化学活化法所需活化剂用量大（如KOH与前驱体质量比常达3:1甚至4:1），不仅大幅增加了制备成本，还带来后续酸洗废液处理量大、设备腐蚀严重及环境污染等突出问题
[0005]鉴于此，本发明的目的在于通过高温熔融盐体系协助生物质与煤实现界面接触与反应均匀性的显著提升，并以高温液相熔融盐作用进行原位无机模板构筑、异质原子掺杂与层间结构撑开稳定，从而实现高性能煤基多孔碳材料的制备和应用。本发明提供的煤基多孔碳材料的制备方法操作简单、高效，将煤与生物质、H3BO3和K2CO3球磨混合后碳化，经无机熔融盐流体引发高温液相原位模板构筑与异质原子掺杂，预先在碳骨架中引入丰富的硼、钾活性位点并实现分子交联与层间结构撑开，有效防止了碳基体在高温下的过度烧结并稳定初始孔隙骨架，同时液相熔融盐使活化刻蚀反应分布更加温和且彻底以协同促进高效均匀造孔，反应产物经后续洗涤、干燥即得煤基多孔碳材料。将由此方法制备的煤基多孔碳材料用于储能领域时表现出高比表面积和快速的离子传输能力。
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Figure CN122586038A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of porous carbon materials technology, and in particular to a method for preparing coal-based porous carbon materials and their applications. Background Technology
[0002] Coal is a carbon-rich, complex solid organic mixture formed from plant remains through complex geological processes. Industrially, it is generally classified into three main categories: lignite, bituminous coal, and anthracite. Lignite is a natural mineral with a low degree of coalification. Under normal conditions, it readily absorbs water and is easily weathered and fragmented. Its physical and chemical stability is poor, and its low calorific value and significant greenhouse gas and pollutant emissions during direct combustion severely restrict its environmental and clean utilization. Bituminous and anthracite, on the other hand, originate from deeper strata and undergo longer geological evolution. At room temperature, they are mostly black, dense lumps or hard solids. Currently, they are primarily used in traditional energy and heavy industry sectors such as thermal power generation, steel metallurgy, and bulk basic chemicals, resulting in relatively low overall added value. To break through the limitations of traditional low-end applications and significantly improve economic efficiency, using low-cost coal as a carbon source precursor and designing high-performance porous carbon materials for energy storage electrodes with excellent conductive networks, high specific surface area, and rich, tunable pore structures has become an important approach to achieving the high-value transformation of coal resources.
[0003] Currently, the main methods for preparing coal-based porous carbon include activation, template methods, and heteroatom doping methods. Among these, activation is the most widely used due to its relatively simple operation and high tunability of pore structure. Activation can be further divided into physical activation and chemical activation. Physical activation typically uses CO2 or water vapor to etch and create pores in the carbon precursor at high temperatures, but this method often suffers from high activation temperatures, low pore-forming efficiency, and insufficiently developed pore structures. Chemical activation utilizes activators such as KOH, H3PO4, and ZnCl2 to react chemically with carbon materials to achieve pore formation, resulting in porous carbon with high specific surface area and abundant pore structure. However, traditional chemical activation methods, represented by KOH, require large amounts of activator (e.g., the mass ratio of KOH to precursor is often 3:1 or even 4:1), which not only significantly increases the preparation cost but also leads to prominent problems such as large volumes of subsequent pickling wastewater, severe equipment corrosion, and environmental pollution. Therefore, how to prepare coal-based porous carbon materials with well-developed pore structures under mild conditions has become a pressing technical challenge in this field.
[0004] Based on this, the present invention proposes a method for preparing coal-based porous carbon materials based on a boric acid and potassium carbonate molten salt system. This method utilizes the eutectic salt system formed by boric acid and potassium carbonate under heating conditions. Taking advantage of the uniform contact and high mass transfer efficiency of the molten salt liquid phase, the activated components can interact more fully and uniformly with the coal matrix, thereby efficiently constructing the porous structure of the coal-based carbon material. Summary of the Invention
[0005] Therefore, the purpose of this invention is to significantly improve the interfacial contact and reaction uniformity between biomass and coal through a high-temperature molten salt system, and to achieve the preparation and application of high-performance coal-based porous carbon materials through in-situ inorganic template construction, heterogeneous atom doping, and interlayer structure expansion and stabilization using high-temperature liquid-phase molten salt. The preparation method of coal-based porous carbon materials provided by this invention is simple and efficient. Coal, biomass, H3BO3, and K2CO3 are ball-milled and carbonized. High-temperature liquid-phase in-situ template construction and heterogeneous atom doping are initiated by inorganic molten salt fluid. Abundant boron and potassium active sites are introduced into the carbon framework beforehand, achieving molecular cross-linking and interlayer structure expansion. This effectively prevents excessive sintering of the carbon matrix at high temperatures and stabilizes the initial pore framework. Simultaneously, the liquid-phase molten salt makes the activation etching reaction distribution more gentle and thorough, synergistically promoting efficient and uniform pore formation. The reaction product is then washed and dried to obtain the coal-based porous carbon material. When used in the energy storage field, the coal-based porous carbon material prepared by this method exhibits high specific surface area and rapid ion transport capabilities.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing coal-based porous carbon materials, comprising the following steps: (1) Mix coal, biomass, H3BO3 and K2CO3 evenly; (2) Carbonize the material after uniform mixing in step (1) to obtain coal-based porous carbon material.
[0007] Preferably, the coal in step (1) is one of lignite, bituminous coal, or anthracite; the biomass is one of lignocellulosic, nitrogen-rich / protein-rich, algae, polyphenol-rich / extract-rich, or polysaccharide-rich.
[0008] Preferably, in step (1), the mass ratio of coal to biomass is 1:0.1 to 1:3; the mass ratio of coal to H3BO3 is 1:2 to 1:10; and the mass ratio of coal to K2CO3 is 1:2 to 1:10.
[0009] Preferably, in step (1), the mixing method of coal, biomass, H3BO3 and K2CO3 is one of physical mixing, wet mixing and chemical-assisted mixing.
[0010] Preferably, the carbonization atmosphere in step (2) is air or an inert atmosphere, and the inert atmosphere includes at least one of nitrogen, helium, argon, neon and xenon.
[0011] Preferably, the carbonization temperature in step (2) is 650~950℃, and the heating rate is 1~10℃ min. -1The carbonization time is 1~5 h.
[0012] This invention also provides coal-based porous carbon materials prepared by the preparation method described above. The prepared coal-based porous carbon materials can be applied to lithium-ion battery anode materials, zinc-ion hybrid capacitor cathode materials, lithium-sulfur battery sulfur cathode carriers, sodium-ion battery anode materials, and supercapacitor double-layer electrode materials. Attached Figure Description
[0013] Figure 1 The curves show the rate performance of the porous carbon material in Example 1.
[0014] Figure 2 This is a SEM image of the porous carbon material in Example 2.
[0015] Figure 3 The porous carbon material in Example 2 at 0.1 A g -1 The GCD test curve. Detailed Implementation
[0016] This invention provides a method for preparing coal-based porous carbon materials, comprising the following steps: (1) Mix coal, biomass, H3BO3 and K2CO3 evenly; (2) Carbonize the material after uniform mixing in step (1) to obtain coal-based porous carbon material.
[0017] In this invention, the coal is one of lignite, bituminous coal, or anthracite; the biomass is preferably one of lignocellulosic, nitrogen-rich / protein-rich, algae, polyphenol / extract-rich, or polysaccharide-rich. Both the coal and biomass mentioned above can be purchased. The lignocellulosic includes cellulose, corn cobs, sawdust, straw, bagasse, rice husks, and bamboo, etc.; the algae includes seaweed and microalgae, etc.; the polyphenol / extract-rich includes coffee grounds, tea leaves, peanut skins, and flower petals, etc.; the polysaccharides include nitrogen-rich / protein-rich, such as soybean residue and peptone, etc.
[0018] In this invention, the mixing method for coal, biomass, H3BO3, and K2CO3 is one of physical mixing, wet mixing, or chemically assisted mixing. Physical mixing can be selected from dry mechanical mixing, mechanical ball milling, melt blending, or ultrasonically assisted mixing; wet mixing can be selected from solvent mixing or slurry mixing; and the chemically assisted method is surface modification. Among these mixing methods, mechanical ball milling is preferred for its simplicity and ease of operation. The purpose of the selected mixing method is to ensure uniform mixing of the two materials, guaranteeing the homogeneity of the prepared carbon material.
[0019] In this invention, the preferred mass ratio of coal to biomass is 1:0.1 to 1:3, more preferably 1:0.1 to 1:1; the preferred mass ratio of coal to H3BO3 is 1:2 to 1:10, more preferably 1:3 to 1:7; and the preferred mass ratio of coal to K2CO3 is 1:2 to 1:10, more preferably 1:3 to 1:7. In this invention, the carbonization atmosphere is air or an inert atmosphere, including at least one of nitrogen, helium, argon, neon and xenon, more preferably one of air, nitrogen and argon.
[0020] In this invention, the carbonization temperature is preferably 650~950℃, more preferably 700~900℃. The heating rate is preferably 1~10℃ / min. -1 More preferably 5~8 ℃ min -1 The carbonization time is preferably 1 to 5 hours, more preferably 2 to 3 hours. In this invention, when the carbonization temperature, time, and heating rate are within the above ranges, coal-based porous carbon materials with excellent electrochemical properties can be obtained.
[0021] In this invention, the prepared coal-based porous carbon material needs to undergo impurity removal treatment. This impurity removal involves immersing the carbonization product in a dilute HCl solution, heating and stirring for 3-10 hours, then filtering, washing several times with deionized water, and finally drying. In this invention, the concentration of the dilute HCl solution is preferably 1 M. The drying method can be any one of vacuum drying, oven drying, and freeze drying.
[0022] This invention also provides the application of the coal-based porous carbon materials described above in lithium-ion battery anode materials, zinc-ion hybrid capacitor cathode materials, lithium-sulfur battery sulfur cathode carriers, sodium-ion battery anode materials, and supercapacitor double-layer electrode materials.
[0023] The present invention does not specifically limit the application method of the coal-based porous carbon material in the electrode material. Any carbon material well known to those skilled in the art can be used as the application method in the above system.
[0024] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Example 1
[0025] Coal, coffee grounds, H3BO3, and K2CO3 in a ratio of 1:1:4:7 were ball-milled and placed in a tube furnace. Under the protection of high-purity argon, the mixture was heated at 5 °C for 1 min. -1The sample was heated to 900℃ and held for 2 hours. After naturally cooling to room temperature, the carbonized sample was collected, soaked in a 1 M HCl hot solution for 6 hours to remove impurities, washed several times with deionized water, and dried at 60℃ for 12 hours to obtain coal-based porous carbon material.
[0026] The coal-based porous carbon material prepared in Example 1 was mixed with acetylene black and PTFE at a mass ratio of 8:1:1, and cut into pieces with a diameter of 10 mm. 2 The electrodes were prepared for use (the active material mass loading was approximately 1.6 mg). In this experiment, the zinc-ion capacitor was assembled in the form of a CR2032 coin cell. Coal-based porous carbon and zinc foil were used as the positive and negative electrodes, respectively; Whatman glass fiber was used as the separator; and 1 M Zn(CF3SO3)2 aqueous solution was used as the electrolyte.
[0027] The assembled batteries were subjected to charge-discharge performance tests at 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 A g. -1 The test was conducted at a current density of 0.1 A g, and then returned to 0.1 A g. -1 The resulting battery charge / discharge rate curve is shown in the figure below. Figure 1 As shown. From Figure 1 It can be seen that the battery prepared in Example 1 has a performance of 0.1 A g. -1 The reversible specific capacity is 159.60 mAh g. -1 . Example 2
[0028] Coal, coffee grounds, H3BO3, and K2CO3 in a ratio of 3:1:5:9 were ball-milled and then placed in a tube furnace. Under the protection of high-purity argon, the mixture was heated at 5 °C for 1 min. -1 The sample was heated to 700℃ and held for 2 hours. After naturally cooling to room temperature, the carbonized sample was collected, soaked in a 1 M HCl hot solution for 6 hours to remove impurities, washed several times with deionized water, and dried at 60℃ for 12 hours to obtain coal-based porous carbon material.
[0029] The coal-based porous carbon material prepared in Example 2 was scanned by SEM, as shown below. Figure 2 As shown, the prepared carbon material has an observable pore structure.
[0030] The coal-based porous carbon material prepared in Example 2 was mixed with acetylene black and PTFE at a mass ratio of 8:1:1, and cut into pieces with a diameter of 10 mm. 2The electrodes were prepared for use (the active material mass loading was approximately 1.6 mg). In this experiment, the zinc-ion capacitor was assembled in the form of a CR2032 coin cell. Coal-based porous carbon and zinc foil were used as the positive and negative electrodes, respectively; Whatman glass fiber was used as the separator; and 1 M Zn(CF3SO3)2 aqueous solution was used as the electrolyte.
[0031] The assembled battery was subjected to charge-discharge performance testing. The battery prepared in Example 2 showed a charge-discharge performance of 0.1 A g. -1 The GCD curve is as follows Figure 3 As shown. From Figure 3 It can be seen that the battery prepared in Example 2 has a performance of 0.1 A g. -1 The reversible specific capacity is 122.63 mAh g. -1 . Example 3
[0032] Coal, spirulina, H3BO3, and K2CO3 in a ratio of 1:1:4:7 were ball-milled and then placed in a tube furnace. Under the protection of high-purity argon, the mixture was heated at 5 °C for 1 min. -1 The sample was heated to 900℃ and held for 2 hours. After naturally cooling to room temperature, the carbonized sample was collected, soaked in a 1 M HCl hot solution for 6 hours to remove impurities, washed several times with deionized water, and dried at 60℃ for 12 hours to obtain coal-based porous carbon material.
Claims
1. A method for preparing a coal-based porous carbon material, comprising the following steps: (1) Mix coal, biomass, H3BO3 and K2CO3 evenly; (2) Carbonize the material after uniform mixing in step (1) to obtain coal-based porous carbon material.
2. The preparation method according to claim 1, characterized in that, The coal in step (1) is one of lignite, bituminous coal, or anthracite; the biomass is one of lignocellulose, nitrogen-rich / protein, algae, polyphenol / extract-rich, or polysaccharide.
3. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of coal to biomass is 1:0.1 to 1:3; the mass ratio of coal to H3BO3 is 1:2 to 1:10; and the mass ratio of coal to K2CO3 is 1:2 to 1:
10.
4. The preparation method according to claim 1, characterized in that, In step (1), the mixing method of coal, biomass, H3BO3 and K2CO3 is one of physical mixing, wet mixing and chemical-assisted mixing.
5. The preparation method according to claim 1, characterized in that, The carbonization atmosphere in step (2) is air or an inert atmosphere, and the inert atmosphere includes at least one of nitrogen, helium, argon, neon and xenon.
6. The preparation method according to claim 1, characterized in that, The carbonization temperature in step (2) is 650~950℃, and the heating rate is 1~10℃ min. -1 The carbonization time is 1~5 h.
7. The coal-based porous carbon material prepared by the preparation method according to any one of claims 1 to 6 and its application. The prepared coal-based porous carbon material can be used as a negative electrode material for lithium-ion batteries, a positive electrode material for zinc-ion hybrid capacitors, a sulfur positive electrode carrier for lithium-sulfur batteries, a negative electrode material for sodium-ion batteries, and a double-layer electrode material for supercapacitors.