Biomass-based porous carbon material, method for preparing the same, and use thereof

Abstract

The application discloses a biomass-based porous carbon material and a preparation method and application thereof, and relates to the technical field of negative electrode materials. The macropores of a biomass raw material are selectively filled by fungi, and the carbonized mycelium after carbonization retains a fibrous or three-dimensional interwoven network shape, so that the proportion of macropores of the biomass-based carbon skeleton is significantly reduced, the side pressure strength is significantly improved while the pore size distribution is optimized, the volume expansion of silicon is effectively buffered, and the electrode structure integrity is maintained; the electronic transmission is fast, the rate performance and the coulomb efficiency are improved. The organic waste is used as a carbon source, the source is wide, the cost is low, the high-value utilization of the waste is realized, the economic benefit and the environmental benefit are combined, and the preparation method is simple in process, mild in condition and easy to scale production.

Description

Technical Field

[0001] This invention relates to the field of anode material technology, and more specifically, to biomass-based porous carbon materials, their preparation methods, and applications. Background Technology

[0002] Silicon-based materials are considered one of the most promising next-generation lithium-ion battery anode materials due to their ultra-high theoretical specific capacity, moderate lithium intercalation potential, and abundant crustal reserves. However, silicon undergoes a massive volume expansion (approximately 300%) during charge and discharge, leading to electrode material pulverization, conductive network breakage, and instability of the solid electrolyte interface film, severely hindering the commercial application of silicon-based anode materials. In the research of silicon-based anode materials, the composite of nano-silicon and porous carbon is considered an effective way to solve the silicon volume expansion problem.

[0003] Biomass waste, due to its renewability, low cost, and structural diversity, has become an important precursor source for the preparation of porous carbon materials. However, these materials often suffer from problems such as an excessively high proportion of macropores, insufficient mechanical strength, and poor conductivity. Although these properties can be partially improved by adding conductive fillers or using specific precursors, challenges remain, including complex processes, high costs, and limited structural control. In particular, when applied to silicon-carbon composite anodes, existing biomass-based porous carbon materials struggle to simultaneously meet the multiple requirements of pore structure optimization, improved mechanical strength, and enhanced conductivity.

[0004] To address these issues, previous studies have attempted to introduce conductive agents such as carbon nanotubes, graphene, or conductive carbon black into porous carbon for composite modification. However, these methods suffer from problems such as high cost, uneven dispersion, and complex processes. Furthermore, the preparation of porous carbon materials using fungal mycelium directly as a carbon precursor has been reported. However, in this method, the mycelium itself is the carbon source, and the morphology and pore structure of the product are limited by the mycelium's own morphology, making it difficult to directionally control carbon supports with specific pore structure requirements.

[0005] Therefore, there is an urgent need to develop a modification method that can simultaneously optimize the pore structure distribution of biomass-based porous carbon materials, improve mechanical strength, and enhance conductivity. This method should also be characterized by simple process, low cost, and wide availability of raw materials to meet the performance requirements of silicon-carbon anodes for carbon carriers.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide biomass-based porous carbon materials, their preparation methods, and applications, in order to solve or improve the above-mentioned technical problems.

[0008] This invention is implemented as follows: In a first aspect, the present invention provides a biomass-based porous carbon material, comprising: carbonized mycelium and a biomass-based carbon skeleton, wherein the carbonized mycelium is distributed in the pores and / or surface of the biomass-based carbon skeleton in a fibrous or three-dimensional interwoven network form. Among them, biomass-based porous carbon materials include hierarchical pore structures.

[0009] In an optional embodiment, the carbonized mycelium includes at least one of features (1) to (16): (1) When the carbonized mycelium is fibrous, its carbonization remnant morphology is selected from at least one of spiral, racket-shaped, antler-shaped, flat ribbon-shaped and sheet-shaped; (2) Carbonized mycelium is solid or hollow and has branches; (3) The carbonization morphology of carbonized mycelium includes septate mycelium and / or non-septate mycelium; when the carbonization morphology is septate mycelium, it has a septate remnant structure; (4) When the carbonized mycelium has a three-dimensional interwoven network structure, the three-dimensional interwoven network structure is formed by the entanglement, overlap and / or branching connection between the carbonized mycelium fibers; (5) The diameter of a single fiber of carbonized mycelium is 1 μm-20 μm, the fiber length is 50 μm-500 μm, the fiber segment length is 40 μm-60 μm, and the branch length is 10 μm-20 μm; (6) The carbonized mycelium is arranged in a random interweaving or directional pattern; (7) The density of carbonized mycelium was 1.2 g / cm³. 3 -1.8 g / cm 3 ; (8) The carbonization shrinkage rate of carbonized mycelium is 20%-50%.

[0010] In an optional embodiment, the carbonized mycelium further includes at least one of features (9) to (15): (9) The carbon interlayer spacing d corresponding to the (002) crystal plane in the X-ray diffraction pattern of carbonized mycelium 002 The size ranges from 0.34 nm to 0.42 nm; the carbon interlayer spacing contains short-range ordered onion-like graphitic carbon structures, with the ordered regions of the onion-like graphitic carbon structures having a size of 3 nm to 4 nm. (10) The intensity ratio of the D peak to the G peak in the Raman spectrum of carbonized mycelium I D / I G The ratio is 0.5-1.4; (11) In the carbonized mycelium, the carbon content is 80wt%-95wt%, the oxygen content is 0.2wt%-9.1wt%, and the nitrogen content is 0.8wt%-4.8wt%; (12) The specific surface area of ​​the carbonized mycelium is 60 m². 2 / g-300 m 2 / g, pore volume 0.05 cm³ 3 / g-0.25 cm 3 / g, with an average pore size of 15 nm-25 nm; (13) The nitrogen-doped configuration of the carbonized mycelium includes at least one of pyridine nitrogen, pyrrole nitrogen, graphitic nitrogen and nitrogen oxides; wherein the pyridine nitrogen content is 10%-29% and the graphitic nitrogen content is 15%-35%; (14) The water contact angle of carbonized mycelium is 60°-150°; (15) The electrical conductivity of carbonized mycelium is 0.7 S / cm-30 S / cm.

[0011] In an optional embodiment, the biomass-based porous carbon material includes at least one of features (1) to (6): (1) The hierarchical pore structure of biomass-based porous carbon materials includes at least two of the following: micropores, mesopores and macropores; Among them, micropores account for 40%-80%; mesopores account for 10%-80%; and macropores account for 1%-15%.

[0012] (2) The BET specific surface area of ​​the biomass-based porous carbon material is 800 m². 2 / g-2800 m 2 / g, pore volume 0.5 cm³ 3 / g-1.5 cm 3 / g; (3) The average pore size of the biomass-based porous carbon material is 0.5 nm-6 nm, preferably 1.5 nm-4 nm; (4) In biomass-based porous carbon materials, the pore volume of micropores accounts for 40%-90% of the total pore volume; (5) Biomass-based porous carbon materials include a three-dimensional interwoven network framework derived from carbonized mycelium, which is formed by the intertwining and overlapping of carbonized mycelium fibers. (6) Biomass-based porous carbon materials have a honeycomb or sponge-like porous microstructure.

[0013] In an optional embodiment, the biomass-based porous carbon material further includes at least one of features (7) to (13): (7) Biomass-based porous carbon materials have an amorphous carbon structure. The carbon interlayer spacing d corresponding to the (002) crystal plane in its X-ray diffraction pattern is... 002 The wavelength ranges from 0.36 nm to 0.42 nm. (8) The intensity ratio of the D peak to the G peak in the Raman spectrum of biomass-based porous carbon materials I D / I G The value is 0.8-1.6; (9) The biomass-based porous carbon material has a carbon content of 80wt%-95wt%, a nitrogen content of 0.1wt%-5wt%, and an oxygen content of 0.1wt%-10wt%; (10) The electrical conductivity of biomass-based porous carbon materials is 0.7 S / cm-30 S / cm; (11) The graphitization degree of the biomass-based porous carbon material is 5%-50%, preferably 10%-40%; The degree of graphitization is determined by the carbon interlayer spacing d corresponding to the (002) crystal plane in the X-ray diffraction pattern. 002 Calculated according to the Mering-Maire formula; (12) The graphite crystallite size Lc of the biomass-based porous carbon material is 0.5 nm-3.0 nm, and the size La is 0.5 nm-5.0 nm. Lc and La are calculated from the XRD pattern according to the Scherrer formula. (13) The lateral compressive strength of biomass-based porous carbon materials is 120 N / cm-200 N / cm.

[0014] In an optional embodiment, the raw materials for preparing biomass-based porous carbon materials include at least one of features (1) to (3): (1) The raw materials of the biomass-based carbon skeleton include biomass raw materials, which are selected from at least one of distiller's grains, agricultural and forestry waste and animal manure; wherein, distiller's grains include at least one of beer grains, baijiu grains and huangjiu grains; agricultural and forestry wastes include at least one of straw, rice husks, corn cobs, bamboo chips and wood chips; animal manures include at least one of pig manure, cow manure, sheep manure and horse manure; (2) Carbonized mycelium is produced by fungi or actinomycetes. The fungi are selected from at least one of white-rot fungi, Trichoderma, Penicillium and Aspergillus; the actinomycetes are selected from at least one of Streptomyces, Nocardia, Thermomonas and Cellulomonas. (3) Fungi are nitrogen-containing self-doped carbon materials. The nitrogen element comes from the chitin in the cell wall of fungal hyphae, and the nitrogen content is 1%-8%.

[0015] Secondly, the present invention provides a method for preparing a biomass-based porous carbon material as described in any of the foregoing embodiments, comprising the following steps: Biomass feedstock pretreatment is performed to obtain pretreated biomass feedstock; The fungi were fermented in a culture medium containing pretreated biomass raw materials to obtain the precursor. Biomass-based porous carbon materials are prepared by drying, pre-carbonizing, acid washing, and carbonizing the precursor.

[0016] The culture medium includes pretreated biomass raw materials and nutrients, wherein the nutrients include at least one of potato flour, glucose, urea, thiamine, disodium hydrogen phosphate, potassium dihydrogen phosphate and magnesium sulfate.

[0017] In an optional embodiment, the preparation method includes at least one of features (1) to (6): (1) The fermentation temperature in the culture medium is 25℃-40℃, and the time is 3-15 days; (2) Under a protective atmosphere and at a rate of 5℃ / min-10℃ / min, the precursor is pre-carbonized at a temperature of 300℃-500℃ for 1h-4h to obtain pre-carbonized material. (3) The pre-carbonized material is subjected to a first pickling treatment and dried to obtain a first pickling material; (4) The obtained pickling material is heated to 600℃-900℃ under a protective atmosphere and a rate of 5℃ / min-10℃ / min for carbonization treatment for 1h-4h to obtain carbonized material. (5) The carbonized material is activated at a temperature of 600℃-900℃ for 1h-3h to obtain activated material; the activator during the activation process is selected from at least one of CO2, H2O, KOH, NaOH and ZnCl2. (6) When the activator is at least one of CO2, KOH, NaOH and ZnCl2, the activator needs to be subjected to secondary pickling and drying to obtain secondary pickling material.

[0018] Thirdly, the present invention provides an application of a biomass-based porous carbon material as described in any of the foregoing embodiments in anode materials.

[0019] The present invention has the following beneficial effects: The biomass-based porous carbon material provided by this invention utilizes fungi to selectively fill the macropores of the biomass-based carbon framework. The carbonized mycelium retains its fibrous or three-dimensional interwoven network morphology, significantly reducing the proportion of macropores in the biomass-based carbon framework, optimizing pore size distribution, and facilitating uniform loading of nano-silicon. Simultaneously, the carbonized mycelium forms a continuous carbon fiber network within the macropores, tightly bonding with the original carbon framework to provide structural support, significantly improving lateral pressure resistance, effectively buffering silicon volume expansion, and maintaining electrode structural integrity. Furthermore, the three-dimensional network of the carbonized mycelium constructs a continuous conductive pathway, enhancing conductivity, facilitating rapid electron transport, and improving rate performance and coulombic efficiency. The chitin in the mycelial cell walls is rich in nitrogen, forming a self-doped carbon material with high nitrogen content after carbonization, which improves electronic conductivity and affinity for silicon, and enhances interfacial stability.

[0020] This invention uses organic waste such as distiller's grains and agricultural and forestry waste as carbon sources, which are widely available and inexpensive, realizing the high-value utilization of waste and achieving both economic and environmental benefits. Moreover, the preparation method is simple, mild, and easy to scale up. The pore structure and performance can be flexibly adjusted by controlling the strain, culture conditions and carbonization parameters, and it can be used to prepare silicon-carbon anode materials. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a diagram showing the morphology of fungal hyphae. Figure 2 This is a morphological diagram of carbonized mycelia; Figure 3 The results of the contact angle test for carbonized mycelium; Figure 4 X-ray diffraction pattern of carbonized mycelium; Figure 5 The BET curves are for biomass-based porous carbon materials. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0024] In a first aspect, the present invention provides a biomass-based porous carbon material, comprising: carbonized mycelium and a biomass-based carbon skeleton, wherein the carbonized mycelium is distributed in the pores and / or surface of the biomass-based carbon skeleton in a fibrous or three-dimensional interwoven network form. Among them, biomass-based porous carbon materials include hierarchical pore structures.

[0025] It should be noted that the carbonized mycelium and the biomass-based carbon skeleton are bonded at a homogeneous carbon-carbon interface. The carbonized mycelium grows in the macropores of the biomass-based carbon skeleton through in-situ carbonization and forms a continuous three-dimensional conductive and support network with the biomass-based carbon skeleton.

[0026] In an optional embodiment, the carbonized mycelium includes at least one of features (1) to (16): (1) When the carbonized mycelium is fibrous, its carbonization remnant morphology is selected from at least one of spiral, racket-shaped, antler-shaped, flat ribbon-shaped and sheet-shaped; (2) Carbonized mycelium is solid or hollow and has branches; the branches in carbonized mycelium are natural branches.

[0027] (3) The carbonization morphology of carbonized mycelium includes septate mycelium and / or non-septate mycelium; when the carbonization morphology is septate mycelium, it has a septate remnant structure; (4) When the carbonized mycelium has a three-dimensional interwoven network structure, the three-dimensional interwoven network structure is formed by the entanglement, overlap and / or branching connection between the carbonized mycelium fibers; (5) The diameter of a single fiber of the carbonized mycelium is 1 μm-20 μm, the fiber length is 50 μm-500 μm, the fiber segment length is 40 μm-60 μm, and the branch length is 10 μm-20 μm; the morphology diagram of the carbonized mycelium is shown in the figure. Figure 2 .

[0028] (6) The carbonized mycelium is arranged in a random interweaving or directional pattern; (7) The density of carbonized mycelium was 1.2 g / cm³. 3 -1.8 g / cm 3 ; (8) The carbonization shrinkage rate of carbonized mycelium is 20%-50%.

[0029] In an optional embodiment, the carbonized mycelium further includes at least one of features (9) to (15): (9) The carbon interlayer spacing d corresponding to the (002) crystal plane in the X-ray diffraction pattern of carbonized mycelium 002The wavelength ranges from 0.34 nm to 0.42 nm; the interlayer spacing contains short-range ordered onion-like graphitic carbon structures, with ordered regions of 3 nm to 4 nm in size; the X-ray diffraction pattern of the carbonized mycelium is shown in [reference needed]. Figure 4 .

[0030] (10) The intensity ratio of the D peak to the G peak in the Raman spectrum of carbonized mycelium I D / I G The ratio is 0.5-1.4; (11) In the carbonized mycelium, the carbon content is 80wt%-95wt%, the oxygen content is 0.2wt%-9.1wt%, and the nitrogen content is 0.8wt%-4.8wt%; It should be noted that the raw material used for carbonized mycelium is fungus. The fungus used in the embodiments of the present invention is a nitrogen-containing self-doped carbon material. The nitrogen element comes from the chitin in the cell wall of the fungal mycelium, and the nitrogen content is 1%-8%.

[0031] (12) The specific surface area of ​​the carbonized mycelium is 60 m². 2 / g-300 m 2 / g, pore volume 0.05 cm³ 3 / g-0.25 cm 3 / g, with an average pore size of 15 nm-25 nm; (13) The nitrogen-doped configuration of the carbonized mycelium includes at least one of pyridine nitrogen, pyrrole nitrogen, graphitic nitrogen and nitrogen oxides; wherein the pyridine nitrogen content is 10%-29% and the graphitic nitrogen content is 15%-35%; Furthermore, the surface of carbonized mycelium contains oxygen- and nitrogen-containing functional groups such as CO, CN, C=O, and OC=O.

[0032] (14) The water contact angle of carbonized mycelium is 60°-150°; the contact angle test results are shown in […]. Figure 3 .

[0033] (15) The electrical conductivity of carbonized mycelium is 0.7 S / cm-30 S / cm.

[0034] In an optional embodiment, the biomass-based porous carbon material includes at least one of features (1) to (6). (1) The hierarchical pore structure of biomass-based porous carbon materials includes at least two of the following: micropores, mesopores and macropores; Among them, micropores account for 40%-80%; mesopores account for 10%-80%; and macropores account for 1%-15%. It should be noted that, compared with the control biomass-based porous carbon material without mycelium filling, the proportion of macropores in the biomass-based porous carbon material prepared by fungal fermentation culture provided in the embodiments of the present invention is reduced by 5%-20%, while the proportion of mesopores and micropores is relatively increased.

[0035] (2) The BET specific surface area of ​​the biomass-based porous carbon material is 800 m². 2 / g-2800 m 2 / g, pore volume 0.5cm 3 / g-1.5 cm 3 / g; (3) The average pore size of the biomass-based porous carbon material is 0.5 nm-6 nm, preferably 1.5 nm-4 nm; (4) In biomass-based porous carbon materials, the pore volume of micropores accounts for 40%-90% of the total pore volume; (5) Biomass-based porous carbon materials include a three-dimensional interwoven network framework derived from carbonized mycelium, which is formed by the intertwining and overlapping of carbonized mycelium fibers. (6) Biomass-based porous carbon materials have a honeycomb or sponge-like porous microstructure.

[0036] In an optional embodiment, the biomass-based porous carbon material further includes at least one of features (7) to (13): (7) Biomass-based porous carbon materials have an amorphous carbon structure. The carbon interlayer spacing d corresponding to the (002) crystal plane in its X-ray diffraction pattern is... 002 The wavelength ranges from 0.36 nm to 0.42 nm. (8) The intensity ratio of the D peak to the G peak in the Raman spectrum of biomass-based porous carbon materials I D / I G The value is 0.8-1.6; (9) The biomass-based porous carbon material has a carbon content of 80wt%-95wt%, a nitrogen content of 0.1wt%-5wt%, and an oxygen content of 0.1wt%-10wt%; Furthermore, the biomass-based porous carbon material has a carbon content of 80wt%-88wt%, a nitrogen content of 2.1wt%-3.5wt%, and an oxygen content of 8.5wt%-11.5wt%.

[0037] (10) The electrical conductivity of the biomass-based porous carbon material is 0.7 S / cm-30 S / cm; compared with the control biomass-based porous carbon material without mycelium filling, the electrical conductivity is increased by more than 20%.

[0038] (11) The graphitization degree of the biomass-based porous carbon material is 5%-50%, preferably 10%-40%; The degree of graphitization is determined by the carbon interlayer spacing d corresponding to the (002) crystal plane in the X-ray diffraction pattern. 002 Calculated according to the Mering-Maire formula; It should be noted that the degree of graphitization (g) calculated based on XRD data is obtained according to the Mering-Maire formula, g = (0.3440 - d) / (2π) * d ... 002 ) / (0.3440-0.3354)×100% (Equation-1); In Equation-1, 0.3440 nm is the interlayer spacing of completely disordered carbon, and 0.3354 nm is the interlayer spacing of ideal graphite.

[0039] When d 002 When the wavelength is 0.42 nm, g ≈ 0% (completely disordered); When d 002 When the wavelength is 0.36 nm, g ≈ 24.4%; When d 002 When the wavelength is 0.34 nm, g ≈ 46.5%.

[0040] (12) The graphite crystallite size Lc of the biomass-based porous carbon material is 0.5 nm-3.0 nm, and the size La is 0.5 nm-5.0 nm. Lc and La are calculated from the XRD pattern according to the Scherrer formula. It should be noted that the graphite crystallite sizes Lc and La are calculated using the Scherrer formula, as follows: .

[0041] (13) The lateral compressive strength of biomass-based porous carbon materials is 120 N / cm-200 N / cm.

[0042] In an optional embodiment, the raw materials for preparing biomass-based porous carbon materials include at least one of features (1) to (3): (1) The raw materials of the biomass-based carbon skeleton include biomass raw materials, which are selected from at least one of distiller's grains, agricultural and forestry waste and animal manure; wherein, distiller's grains include at least one of beer grains, baijiu grains and huangjiu grains; agricultural and forestry wastes include at least one of straw, rice husks, corn cobs, bamboo chips and wood chips; animal manures include at least one of pig manure, cow manure, sheep manure and horse manure.

[0043] (2) Carbonized mycelium is produced by fungi or actinomycetes. The fungi are selected from at least one of white-rot fungi, Trichoderma, Penicillium and Aspergillus; the actinomycetes are selected from at least one of Streptomyces, Nocardia, Thermomonas and Cellulomonas.

[0044] For example, such as *Phanerochaete chrysosporium* (… Phanerochaete chrysosporium Rough-skinned side ear ( Pleurotus ostreatus ) and Yunzhi ( Trametes versicolor )wait.

[0045] (3) Fungi are nitrogen-containing self-doped carbon materials. The nitrogen element comes from the chitin in the cell wall of fungal hyphae, and the nitrogen content is 1%-8%.

[0046] Secondly, the present invention provides a method for preparing a biomass-based porous carbon material as described in any of the foregoing embodiments, comprising the following steps: Biomass feedstock pretreatment is performed to obtain pretreated biomass feedstock; The fungi were fermented in a culture medium containing pretreated biomass raw materials to obtain the precursor. Biomass-based porous carbon materials are prepared by drying, pre-carbonizing, acid washing, and carbonizing the precursor.

[0047] The culture medium includes pretreated biomass raw materials and nutrients, wherein the nutrients include at least one of potato flour, glucose, urea, thiamine, disodium hydrogen phosphate, potassium dihydrogen phosphate and magnesium sulfate.

[0048] Among them, the morphological diagram of fungal hyphae is shown in Figure 1 .

[0049] In an optional embodiment, the preparation method includes at least one of features (1) to (6): (1) The fermentation culture temperature in the culture medium is 25℃-40℃ and the time is 3-15 days. Fermentation culture can directionally degrade lignin, cellulose and hemicellulose in biomass to create pores. At the same time, the mycelium produced by the fungus during the growth process will remain in the gaps and serve as a supporting skeleton after carbonization.

[0050] It should be noted that the culture medium is brought to a final volume using distilled water and then autoclaved at 115℃-125℃ for 15-30 minutes. The pH of the culture medium is the pH value of the prepared system and no additional pH adjustment is required.

[0051] (2) Under a protective atmosphere and at a rate of 5℃ / min-10℃ / min, the precursor is pre-carbonized at a temperature of 300℃-500℃ for 1h-4h to obtain pre-carbonized material. It should be noted that during carbonization, non-carbon substances (such as hydrogen, oxygen, and nitrogen) escape in gaseous form, while the remaining carbon atoms rearrange to form an amorphous carbon skeleton with a preliminary porous structure. Furthermore, carbonization helps remove easily decomposable organic components from biomass feedstocks, and the resulting carbon skeleton exhibits excellent thermal stability and chemical inertness, resisting high temperatures and acid / alkali corrosion, ensuring the material's service life under harsh environments. The carbonization process fixes carbon elements from biomass feedstocks and fungi within the biomass-based carbon skeleton, reducing carbon loss.

[0052] The protective gas is selected from at least one of nitrogen, helium, and argon.

[0053] (3) The pre-carbonized material is subjected to a first pickling treatment and dried to obtain a first pickling material; (4) The obtained pickling material is heated to 600℃-900℃ under a protective atmosphere and a rate of 5℃ / min-10℃ / min for carbonization treatment for 1h-4h to obtain carbonized material. (5) The carbonized material is activated at a temperature of 600℃-900℃ for 1h-3h to obtain activated material; the activator during the activation process is selected from at least one of CO2, H2O, KOH, NaOH and ZnCl2.

[0054] (6) When the activator is at least one of CO2, KOH, NaOH and ZnCl2, the activated material needs to be subjected to a second acid washing treatment and dried to obtain a second acid-washed material. At this time, the second acid-washed material is a biomass-based porous carbon material.

[0055] When the activator is H2O, a secondary acid washing treatment is not required. In this case, the activated material obtained after activation treatment is biomass-based porous carbon material.

[0056] It should be noted that primary and secondary acid washing are conventional treatment methods in the art, and this invention does not impose any particular limitations on the process parameters or reagents for primary and secondary acid washing. For example, in one embodiment of this invention, 2 mol / L HCl is used for a primary acid washing treatment at 90°C for 2 hours. In other embodiments of this invention, the process parameters and reagent types for primary and secondary acid washing can be reasonably adjusted according to actual needs.

[0057] In an optional embodiment, the pretreatment of biomass raw materials includes washing, filtering, drying and crushing the biomass raw materials to obtain pretreated biomass raw materials.

[0058] The preprocessing method is not particularly limited and can be chosen reasonably according to actual needs. The significance of each operation in preprocessing is analyzed as follows: The cleaning process removes contaminants such as silt, dust, metal, and stones from the surface of biomass raw materials; it prevents filter clogging during the filtration process, ensuring thorough cleaning, and avoids equipment damage or safety hazards during the crushing process. Furthermore, the cleaning process removes soluble salts, preventing unnecessary side reactions during carbonization.

[0059] Crushing is used to reduce the particle size of biomass feedstock and improve reaction efficiency.

[0060] In optional implementations, the pore structure and properties of biomass-based porous carbon materials can be flexibly adjusted by regulating the fungal species, fermentation culture conditions, and carbonization treatment parameters to meet the needs of different application scenarios.

[0061] Thirdly, the present invention provides an application of a biomass-based porous carbon material as described in any of the foregoing embodiments in anode materials.

[0062] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0063] Example 1 This embodiment provides a biomass-based porous carbon material, the preparation method of which includes the following steps: (1) Biomass feedstock pretreatment The biomass raw material is corn stalks, which are then washed, filtered, dried, and crushed to obtain pretreated biomass raw materials.

[0064] (2) Fermentation culture The fungus (Phanerochaete chrysosporium, Phanerochaete chrysosporium The precursor was obtained by fermentation in a culture medium. The culture medium is 200 mL, specifically including the pretreated biomass raw material obtained in step (1) as 1 g, potato flour 6.0 g / L, glucose 20.0 g / L, KH2PO4 3.0 g / L, MgSO4·7H2O 1.5 g / L, and trace amounts of vitamin B.

[0065] The fermentation culture was carried out at a temperature of 28℃ for 7 days. The culture medium was brought to a final volume with distilled water and then sterilized by autoclaving at 121℃ for 20 minutes.

[0066] (3) Preparation of biomass-based porous carbon materials.

[0067] The precursor obtained in step (2) was subjected to drying, pre-carbonization, first acid washing, and carbonization to obtain biomass-based porous carbon material. The drying process was carried out at 60℃ for 12 hours; the pre-carbonization was performed at 400℃ for 2 hours; the first acid washing was performed by stirring at 90℃ with 2 mol / L HCl for 2 hours; and the carbonization was carried out at 700℃ for 2 hours at a rate of 5℃ / min.

[0068] Example 2 This embodiment provides a biomass-based porous carbon material, which is prepared in the same way as in Example 1, except that rice husks are used instead of corn stalks as biomass raw materials.

[0069] Example 3 This embodiment provides a biomass-based porous carbon material, the preparation method of which is the same as that in Example 1, the only difference being the use of *Trametes versicolor* (*Trametes versicolor*). Trametes versicolor ) to replace Proteobacterium chrysosporum ( Phanerochaete chrysosporium ( ) to carry out biological fermentation.

[0070] Example 4 This embodiment provides a biomass-based porous carbon material, which is prepared in the same way as in Example 1, except that an additional activation treatment is performed after carbonization. The specific conditions are: activation with water vapor at 850°C for 2 hours.

[0071] Comparative Example 1 This comparative example provides a biomass-based porous carbon material, which is prepared in the same way as in Example 1, except that it is not prepared through bio-fermentation.

[0072] It should be noted that this comparative example did not involve mycelial fermentation culture of the pretreated biomass raw materials.

[0073] Comparative Example 2 This comparative example provides a biomass-based porous carbon material, which is prepared in the same way as in Example 4, except that it is not prepared through bio-fermentation.

[0074] Test Example 1 This test case analyzed the structural properties of carbonized mycelium in the biomass-based porous carbon materials prepared in Examples 1-4 and Comparative Examples 1-2. The relevant items and results are summarized in Table 1. Fiber morphology, fiber diameter, fiber length, branch length, and arrangement orientation were measured using an optical microscope (OM). I D / I GThe measurements were performed using Raman spectroscopy; carbon, nitrogen, and oxygen content were measured using elemental analysis (CHN / O analysis); specific surface area, pore volume, and average pore size were measured using the BET method (nitrogen adsorption method); electrical conductivity was measured using the four-probe method; and nitrogen doping configuration was measured using X-ray photoelectron spectroscopy (XPS).

[0075] Table 1 Performance parameters of carbonized mycelium structure

[0076] Note: "-" indicates that no corresponding performance data was detected.

[0077] Test Example 2 This test example analyzes the performance of the biomass-based porous carbon materials prepared in Examples 1-4 and Comparative Examples 1-2. The relevant items and results are summarized in Table 2. Specific surface area, pore volume, average pore size, micropore volume ratio, and macropore ratio were measured using the BET method (nitrogen adsorption method). The BET curves are shown in Table 2. Figure 5 Carbon, nitrogen, and oxygen content were measured using an elemental analyzer (CHN / O analysis method); lateral compressive strength was tested according to standards such as ASTM D4179 or ASTM D6175 using a specialized particle strength tester. A single particle was placed sideways on the sample stage, and the instrument applied pressure at a constant rate until the particle was crushed or broken, recording the peak pressure; electrical conductivity was measured using the four-probe method.

[0078] Table 2 Performance parameters of biomass-based porous carbon materials

[0079] Based on the data in Tables 1 and 2, the specific analysis is as follows: Comparing Examples 1-3 with Comparative Example 1, the BET specific surface area (1200 m²) of the material modified with mycelial filling is significantly higher. 2 / g-2300 m 2 / g) and total pore volume (0.49 cm³) 3 / g-1.03 cm 3 / g) and unfilled control material (2850 m) 2 / g, 1.2cm 3 The percentage of macropores remained basically the same, but the proportion of macropores decreased from 18% to 10-15%, while the proportion of micropore volume remained at 60-70% from 72%. This indicates that the carbonized mycelium selectively fills the macropores of the carbon skeleton without damaging the micropore structure, thus achieving the design goal of "filling enhancement without sacrificing specific surface area".

[0080] In terms of lateral compressive strength, Example 1 (168 N / cm) showed a 60% increase compared to Comparative Example 1 (105 N / cm) and a 53% increase compared to Comparative Example 2 (110 N / cm), confirming that the three-dimensional interwoven network of in-situ grown carbonized mycelium has a significant "penetrating" enhancement effect on the carbon skeleton. In contrast, the physical mixture (Comparative Example 2) showed very limited strength improvement due to the lack of effective interfacial bonding and continuous network structure (only increasing from 105 N / cm to 110 N / cm).

[0081] Regarding electrical conductivity, Example 1 (12 S / cm) showed a 150% improvement over Comparative Example 1 (4.8 S / cm) and a 131% improvement over Comparative Example 2 (5.2 S / cm). This indicates that the continuous conductive network formed by the carbonized mycelium in the carbon skeleton effectively compensates for the conductivity interruption caused by the large pores in the carbon skeleton. Furthermore, the in-situ growth method is more effective than physical mixing in achieving close interfacial contact and charge transfer between the carbonized mycelium and the carbon skeleton.

[0082] Regarding nitrogen content, the examples (2.1 wt%-3.5 wt%) were significantly higher than Comparative Example 1 (0.5 wt%), confirming that the natural nitrogen-containing characteristics of mycelium enabled effective in-situ self-doping.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A biomass-based porous carbon material, characterized in that, include: Carbonized mycelium and biomass-based carbon skeleton, wherein the carbonized mycelium is distributed in the pores and / or surface of the biomass-based carbon skeleton in a fibrous or three-dimensional interwoven network form; The biomass-based porous carbon material includes a hierarchical pore structure.

2. The biomass-based porous carbon material according to claim 1, characterized in that, The carbonized mycelium includes at least one of features (1) to (8): (1) When the carbonized mycelium is fibrous, its carbonization residue morphology is selected from at least one of spiral, racket-shaped, antler-shaped, flat ribbon-shaped and sheet-shaped; (2) The carbonized mycelium is solid or hollow and has branches; (3) The carbonization morphology of the carbonized mycelium includes septate mycelium and / or non-septate mycelium; when the carbonization morphology is septate mycelium, it has a septate remnant structure; (4) When the carbonized mycelium has a three-dimensional interwoven network structure, the three-dimensional interwoven network structure is formed by the entanglement, overlap and / or branching connection between the carbonized mycelium fibers; (5) The diameter of a single fiber of the carbonized mycelium is 1 μm-20 μm, the fiber length is 50 μm-500 μm, the fiber segment length is 40 μm-60 μm, and the branch length is 10 μm-20 μm; (6) The carbonized mycelium is arranged in a random interweaving or directional pattern; (7) The density of the carbonized mycelium is 1.2 g / cm³. 3 -1.8 g / cm 3 ; (8) The carbonization shrinkage rate of the carbonized mycelium is 20%-50%.

3. The biomass-based porous carbon material according to claim 1, characterized in that, The carbonized mycelium further includes at least one of features (9) to (15): (9) The carbon interlayer spacing d corresponding to the (002) crystal plane in the X-ray diffraction pattern of the carbonized mycelium. 002 The size is 0.34 nm-0.42 nm; the carbon interlayer spacing contains short-range ordered onion-shaped graphitic carbon structures, and the ordered region size of the onion-shaped graphitic carbon structures is 3 nm-4 nm. (10) The intensity ratio of the D peak to the G peak in the Raman spectrum of the carbonized mycelium I D / I G The ratio is 0.5-1.4; (11) The carbonized mycelium contains 80wt%-95wt% carbon, 0.2wt%-9.1wt% oxygen, and 0.8wt%-4.8wt% nitrogen. (12) The specific surface area of ​​the carbonized mycelium is 60 m². 2 / g-300 m 2 / g, pore volume 0.05 cm³ 3 / g-0.25 cm 3 / g, with an average pore size of 15 nm-25 nm; (13) The nitrogen-doped configuration of the carbonized mycelium includes at least one of pyridine nitrogen, pyrrole nitrogen, graphitic nitrogen and nitrogen oxides; wherein the pyridine nitrogen content is 10%-29% and the graphitic nitrogen content is 15%-35%; (14) The water contact angle of the carbonized mycelium is 60°-150°; (15) The electrical conductivity of the carbonized mycelium is 0.7 S / cm-30 S / cm.

4. The biomass-based porous carbon material according to claim 1, characterized in that, The biomass-based porous carbon material includes at least one of features (1) to (6): (1) The hierarchical pore structure of the biomass-based porous carbon material includes at least two of the following: micropores, mesopores, and macropores; Among them, micropores account for 40%-80%; mesopores account for 10%-80%; and macropores account for 1%-15%. (2) The BET specific surface area of ​​the biomass-based porous carbon material is 800 m². 2 / g-2800 m 2 / g, pore volume 0.5 cm³ 3 / g-1.5 cm 3 / g; (3) The average pore size of the biomass-based porous carbon material is 0.5 nm-6 nm, preferably 1.5 nm-4 nm; (4) In the biomass-based porous carbon material, the pore volume of micropores accounts for 40%-90% of the total pore volume; (5) The biomass-based porous carbon material includes a three-dimensional interwoven network skeleton derived from carbonized mycelium, wherein the three-dimensional network skeleton is formed by the intertwining and overlapping of carbonized mycelium fibers; (6) The biomass-based porous carbon material has a honeycomb or sponge-like porous micromorphology.

5. The biomass-based porous carbon material according to claim 1, characterized in that, The biomass-based porous carbon material further includes at least one of features (7) to (13): (7) The biomass-based porous carbon material has an amorphous carbon structure, and the carbon interlayer spacing d corresponding to the (002) crystal plane in its X-ray diffraction pattern is... 002 The wavelength ranges from 0.36 nm to 0.42 nm. (8) The intensity ratio of the D peak to the G peak in the Raman spectrum of the biomass-based porous carbon material I D / I G The value is 0.8-1.6; (9) The biomass-based porous carbon material has a carbon content of 80wt%-95wt%, a nitrogen content of 0.1wt%-5wt%, and an oxygen content of 0.1wt%-10wt%. (10) The electrical conductivity of the biomass-based porous carbon material is 0.7 S / cm-30 S / cm; (11) The degree of graphitization of the biomass-based porous carbon material is 5%-50%, preferably 10%-40%; The degree of graphitization is determined by the carbon interlayer spacing d corresponding to the (002) crystal plane in the X-ray diffraction pattern. 002 Calculated according to the Mering-Maire formula; (12) The graphite crystallite size Lc of the biomass-based porous carbon material is 0.5 nm-3.0 nm, and the size La is 0.5 nm-5.0 nm. The Lc and La are calculated from the XRD pattern according to the Scherrer formula. (13) The lateral compressive strength of the biomass-based porous carbon material is 120 N / cm-200 N / cm.

6. The biomass-based porous carbon material according to claim 1, characterized in that, The raw materials for preparing the biomass-based porous carbon material include at least one of features (1) to (3): (1) The raw materials of the biomass-based carbon skeleton include biomass raw materials, which are selected from at least one of distiller's grains, agricultural and forestry waste and animal manure; wherein, the distiller's grains include at least one of beer grains, baijiu grains and huangjiu grains; the agricultural and forestry wastes include at least one of straw, rice husks, corn cobs, bamboo shavings and wood chips; the animal manures include at least one of pig manure, cow manure, sheep manure and horse manure; (2) The carbonized mycelium is produced by fungi or actinomycetes, wherein the fungi are selected from at least one of white-rot fungi, Trichoderma, Penicillium and Aspergillus; and the actinomycetes are selected from at least one of Streptomyces, Nocardia, Thermomonas and Cellulomonas. (3) The fungus is a nitrogen-containing self-doped carbon material, and the nitrogen element comes from the chitin in the cell wall of the fungal hyphae, with a nitrogen content of 1%-8%.

7. A method for preparing a biomass-based porous carbon material as described in any one of claims 1-6, characterized in that, Includes the following steps: Biomass feedstock pretreatment is performed to obtain pretreated biomass feedstock; The fungi were placed in a culture medium containing the pretreated biomass raw material and fermented to obtain the precursor. The precursor is subjected to drying, pre-carbonization, acid washing and carbonization to obtain biomass-based porous carbon material.

8. The preparation method according to claim 7, characterized in that, The culture medium includes pretreated biomass raw materials and nutrients, wherein the nutrients include at least one of potato flour, glucose, urea, thiamine, disodium hydrogen phosphate, potassium dihydrogen phosphate, and magnesium sulfate.

9. The preparation method according to claim 7, characterized in that, The preparation method includes at least one of features (1) to features (6): (1) The fermentation temperature in the culture medium is 25℃-40℃, and the time is 3-15 days; (2) Under a protective atmosphere and at a rate of 5℃ / min-10℃ / min, the precursor is pre-carbonized at a temperature of 300℃-500℃ for a period of 1h-4h to obtain pre-carbonized material. (3) The pre-carbonized material is subjected to a first pickling treatment and dried to obtain a first pickling material; (4) The obtained pickling material is heated to a temperature of 600℃-900℃ in a protective atmosphere at a rate of 5℃ / min-10℃ / min for carbonization treatment for 1h-4h to obtain carbonized material. (5) The carbonized material is activated at a temperature of 600℃-900℃ for 1h-3h to obtain activated material; the activator during the activation process is selected from at least one of CO2, H2O, KOH, NaOH and ZnCl2. (6) When the activator is at least one of CO2, KOH, NaOH and ZnCl2, the activator needs to be subjected to secondary pickling and drying to obtain secondary pickling material.

10. The application of a biomass-based porous carbon material as described in any one of claims 1-6 in anode materials.

Images