Modification method and system of biomass charcoal negative electrode material

Abstract

The embodiment of the invention provides a biomass charcoal negative electrode material modification method and system, and the method comprises the steps: pretreating a biomass raw material for removing impurities and controlling the particle size; pyrolyzing and carbonizing the pretreated biomass raw material to obtain biomass powder, heating to a carbonization temperature at a controllable heating rate under the protection of inert gas, and preserving heat to form primary biochar; mixing the primary biochar with an activator, and performing chemical activation treatment at an activation temperature to regulate and control a pore structure and surface properties and generate an activated product; neutralizing the activated product by using an acid solution and dissolving residual alkaline substances for post-treatment of the activated product; and mixing and drying an anchoring agent and the post-treated activation product to obtain the modified biomass charcoal negative electrode material, and the anchoring agent is selected from a lithium polysulfide compound and is used for anchoring transition metal ions in an electrolyte. According to the invention, the negative electrode interface is protected from being damaged by transition metal ions in electrochemical energy storage.

Description

Modification methods and systems for biomass carbon anode materials Technical Field

[0001] This application relates to the technical field of electrochemical energy storage materials, specifically to methods and systems for modifying biomass carbon anode materials. Background Technology

[0002] With the explosive growth in global demand for renewable energy and electric vehicles, developing novel electrochemical energy storage methods with high energy density, long cycle life, and low cost has become an urgent priority. Lithium-ion batteries, as the current dominant technology, rely heavily on electrode materials for their performance. Commercially available graphite anodes have relatively low theoretical capacity (372 mAh g⁻¹). -1 Furthermore, this limits fast-charging performance; while high-capacity anode materials such as silicon-based materials face significant volume expansion issues, leading to a sharp decline in cycle stability. Similarly, in emerging sodium-ion and lithium-sulfur batteries, finding stable host materials that can efficiently accommodate sodium ions and suppress polysulfide shuttle effects is also a key bottleneck restricting their commercial application.

[0003] Carbon materials have long been core materials for energy storage battery electrodes due to their excellent conductivity and stability. However, traditional graphite and artificial graphite materials are expensive, complex to manufacture, and have limited structural control, making it difficult to meet the dual requirements of performance and cost for next-generation batteries. Therefore, it is crucial to develop novel carbon materials that are widely available, structurally designable, and inexpensive.

[0004] Biomass, as an abundant, renewable, and low-cost carbon precursor, offers a highly promising solution for the preparation of advanced carbon materials. Carbon materials derived from biomass such as wood, straw, and nutshells possess naturally porous structures, demonstrating considerable application potential. However, unmodified raw biomass carbon materials suffer from significant defects that severely limit their application in high-end batteries: for example, their microstructure is uncontrollable, meaning the naturally formed pore structures are mostly closed or disordered, resulting in insufficient specific surface area and porosity, making it difficult to provide sufficient active sites and efficient ion transport channels; furthermore, their electrochemical activity is low, meaning their intrinsic graphitization is low, resulting in poor conductivity and a lack of effective pseudocapacitive active sites, leading to poor specific capacity and rate performance; and finally, their surface is chemically inert: the types and numbers of their surface functional groups are limited, resulting in weak lithium-ion adsorption capacity.

[0005] Therefore, targeted modification of biochar and precise control of its microstructure and surface chemical properties are the only way to unlock its huge potential and transform it from a "potential material" into a "high-performance electrode material". Summary of the Invention

[0006] This application proposes a method and system for modifying biomass carbon anode materials to address the deficiencies of the prior art.

[0007] According to a first aspect of the present application, a method for modifying a biomass char anode material is provided, comprising: pretreating biomass raw materials to remove impurities and control particle size; pyrolyzing and carbonizing the pretreated biomass raw materials into biomass powder, and heating the powder to a carbonization temperature at a controllable heating rate under inert gas protection and holding the temperature thereon to form primary biochar; mixing the primary biochar with an activator and then performing chemical activation treatment at an activation temperature to regulate pore structure and surface properties and generate an activation product; neutralizing and dissolving residual alkaline substances in the activation product with an acid solution for post-treatment of the activation product; mixing an anchoring agent with the post-treated activation product and drying it to obtain a modified biomass char anode material, wherein the anchoring agent is selected from lithium polysulfide compounds and is used to anchor transition metal ions in an electrolyte.

[0008] In some embodiments, the biomass raw material is selected from one of bamboo, coconut shell, fruit shell, bagasse, corn stalk, wheat stalk, cotton stalk, rice husk, and corn cob. The pretreatment of the biomass raw material includes: washing, drying, crushing, and sieving the biomass raw material. Washing the biomass raw material includes repeatedly rinsing it with tap water and / or deionized water. Drying the biomass raw material includes drying it at 105°C for at least 12 hours. Sieving the biomass raw material includes collecting the undersize material through a standard sieve.

[0009] In some embodiments, the pyrolysis carbonization of the pretreated biomass raw material into biomass powder includes: pyrolyzing and carbonizing the pretreated biomass raw material into biomass powder based on a carbonization temperature of 500-600°C, a holding time of 120-200 minutes, and a heating rate of 5°C / minute.

[0010] In some embodiments, the chemical activation treatment of mixing the primary biochar with the activator at an activation temperature includes: based on the conditions of an activation temperature of 800-1000℃, a holding time of 60-120 minutes, a heating rate of 5℃ / minute, and the activator being potassium hydroxide, mixing the primary biochar with the activator and then performing chemical activation treatment at an activation temperature.

[0011] In some embodiments, the anchoring agent includes one or more of Li2S, Li2S2, Li2S4, Li2S6, and Li2S8.

[0012] In some embodiments, mixing the anchoring agent with the post-treated activated product includes mixing the anchoring agent with the post-treated activated product at a mixing ratio of 1:3 to 1:10.

[0013] In some implementations, the mixing ratio is 1:3 to 1:7.

[0014] In some embodiments, neutralizing the activated product with an acid solution includes: neutralizing the activated product with a hydrochloric acid solution and stirring under aeration.

[0015] In some embodiments, the method further includes applying the modified biomass carbon negative electrode material to prepare a supercapacitor, wherein the supercapacitor includes a positive electrode, a negative electrode and an electrolyte, and the negative electrode is made by mixing the modified carbon material with a conductive agent and a binder.

[0016] According to a third aspect of this application, a modification system for biomass char anode material is provided, comprising: a raw material pretreatment module for pretreating biomass raw materials to remove impurities and control particle size; a pyrolysis carbonization module for pyrolyzing and carbonizing the pretreated biomass raw materials into biomass powder, and heating the powder to a carbonization temperature at a controllable heating rate under inert gas protection and holding the temperature to form primary biochar; a chemical activation module for mixing the primary biochar with an activator and performing chemical activation treatment at an activation temperature to regulate pore structure and surface properties and generate activation products; a post-treatment module for neutralizing and dissolving residual alkaline substances in the activation products with an acid solution; and a material generation module for mixing an anchoring agent with the post-treated activation products and drying them to obtain modified biomass char anode material, wherein the anchoring agent is selected from lithium polysulfide compounds and is used to anchor transition metal ions in the electrolyte.

[0017] The beneficial effects of the modification method and system for biomass char anode materials in this application include at least the following: Pre-treatment of biomass raw materials removes surface stains and impurity ions, improves material purity, and avoids unnecessary side reactions introduced by impurities during electrochemical processes, thereby enhancing the initial efficiency and stability of the electrode; particle size control is achieved through sieving, ensuring the uniformity of the biomass powder, facilitating uniform processing in subsequent pyrolysis and activation steps, reducing local hot spots or structural defects, and enhancing the consistency of the final electrode material; pyrolysis carbonization can be carried out under inert gas protection, preventing oxidation or combustion of biomass at high temperatures and maintaining the integrity of the carbon structure; a controllable heating rate ensures a stable pyrolysis process, forming a stable primary biochar framework, providing a conductive basis for subsequent activation, and avoiding pore closure or performance degradation caused by rapid heating; and chemical activation treatment can regulate pore size. By optimizing the structure and surface properties, the specific surface area and the number of active sites are increased, improving the transport path of ions in the electrode. Surface property optimization enhances the material's adsorption capacity for lithium ions, improving rate performance and capacity retention, while providing more loading sites for the anchoring agent. Post-treatment uses acid solutions to neutralize and dissolve residual alkaline substances, preventing alkaline residues from causing electrolyte decomposition or interfacial side reactions after battery assembly, ensuring the chemical stability and safety of the material. The neutralization process improves material purity, reduces interfacial impedance, and extends cycle life. Pre-anchoring treatment mixes and dries the lithium polysulfide anchoring agent with the activation product, allowing the anchoring agent to undergo a redox reaction with high-valence transition metal ions in the electrolyte, reducing their oxidizing properties and inhibiting excessive electrolyte decomposition and gas generation. This improves the stability of the negative electrode interface, reduces DC internal resistance, and enhances battery safety and cycle durability. Attached Figure Description

[0018] Figure 1 is a flowchart illustrating the modification method of biomass carbon anode material according to an embodiment of this application; Figure 2 is a flowchart illustrating a specific implementation of the modification method of biomass carbon anode material according to an embodiment of this application; Figure 3 is a structural schematic diagram illustrating the modification system of biomass carbon anode material according to an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed embodiments of the present application, but merely to illustrate selected embodiments of the present application. Other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are all within the scope of protection of the embodiments of the present application.

[0021] This application discloses a method for modifying biomass char anode materials, which is based on a biomass char anode material modification system. The purpose of this method is to overcome the shortcomings of existing technologies by effectively anchoring transition metal ions (nickel ions, cobalt ions, manganese ions) dissolved from the positive electrode in the electrolyte, protecting the anode interface from damage by transition metal ions, thereby improving cycle performance and high-temperature storage performance. Referring to Figure 1, the method includes steps 110-150.

[0022] Step 110: Pre-treat biomass raw materials to remove impurities and control particle size.

[0023] In some embodiments, the biomass raw material is selected from one of bamboo, coconut shell, fruit shell, bagasse, corn stalk, wheat stalk, cotton stalk, rice husk, and corn cob.

[0024] In some embodiments, the pretreatment of the biomass feedstock includes washing, drying, crushing, and sieving the biomass feedstock.

[0025] For example, cleaning the biomass feedstock includes repeatedly rinsing the biomass feedstock with tap water and / or deionized water.

[0026] For example, drying the biomass feedstock includes drying the biomass feedstock at a temperature of 105°C for at least 12 hours.

[0027] For example, screening the biomass feedstock includes collecting the undersize material by passing the biomass feedstock through a standard sieve.

[0028] In one specific embodiment, the pretreatment of biomass raw materials includes: repeatedly washing the collected raw materials (e.g., coconut shells) with tap water to remove surface stains, and then rinsing them 2-3 times with deionized water to reduce impurity ions. The washed raw materials are then placed in a forced-air drying oven and dried at 105°C for at least 12 hours until the weight no longer changes, completely removing moisture. The dried biomass raw materials are then pulverized into powder using a pulverizer, and the powder is sieved through a standard sieve, with the undersize material collected.

[0029] Step 120: Pyrolysis carbonization of the pretreated biomass raw material into biomass powder, and heating to the carbonization temperature at a controllable heating rate under inert gas protection and holding at the temperature to form primary biochar.

[0030] In some embodiments, the pyrolysis carbonization of the pretreated biomass raw material into biomass powder includes: pyrolyzing and carbonizing the pretreated biomass raw material into biomass powder based on a carbonization temperature of 500-600°C, a holding time of 120-200 minutes, and a heating rate of 5°C / minute.

[0031] In one specific embodiment, the pretreated biomass raw material is pyrolyzed and carbonized into biomass powder. Under inert gas protection, the powder is heated to the carbonization temperature at a controllable rate and held at that temperature to form primary biochar. The process includes: after pretreating the biomass raw material, a suitable amount of sieved biomass powder is spread evenly in a quartz boat. The quartz boat is pushed into the center of the isothermal zone of the quartz tube in a tubular furnace, and both ends of the tubular furnace are sealed. The nitrogen cylinder valve is opened, and a gas flow meter is set to allow nitrogen to flow into the quartz tube at a low rate (e.g., 100-200 mL / min). Simultaneously, the outlet valve at the other end of the tubular furnace is opened, and gas is circulated for 10-20 minutes to remove air (oxygen) from the quartz tube and prevent the material from being oxidized or even burned at high temperatures. The temperature is increased at a rate of 5°C / min until a certain temperature (e.g., 500°C) is reached, at which point the heating is stopped, and the holding time is 120-200 minutes. After the heat preservation period, stop heating and allow the furnace to cool naturally to room temperature under the protection of continuous nitrogen gas. Then, turn off the nitrogen gas and carefully remove the quartz boat. What you will get at this point is black primary biochar.

[0032] Step 130: The primary biochar is mixed with an activator and then chemically activated at an activation temperature to regulate the pore structure and surface properties and generate activated products.

[0033] In some embodiments, the chemical activation treatment of the primary biochar after mixing with the activator at an activation temperature includes: based on the conditions of an activation temperature of 800-1000°C, a holding time of 60-120 minutes, a heating rate of 5°C / minute, and the activator being potassium hydroxide, the primary biochar is mixed with the activator and then chemically activated at the activation temperature.

[0034] For example, the anchoring agent includes one or more of Li2S, Li2S2, Li2S4, Li2S6 and Li2S8.

[0035] In some embodiments, mixing the anchoring agent with the post-treated activated product includes mixing the anchoring agent with the post-treated activated product at a mixing ratio of 1:3 to 1:10.

[0036] Preferably, the mixing ratio is 1:3 to 1:7.

[0037] In one specific embodiment, the chemical activation treatment of the primary biochar mixed with the activator at an activation temperature includes: gently grinding the carbonized block biochar (e.g., block coconut shell) into a fine powder in an agate mortar, and accurately weighing the biochar powder using an electronic balance. According to a certain activation ratio, weigh the corresponding mass of KOH solid, and place the biochar powder and KOH powder in a mortar or beaker, mixing them thoroughly and uniformly. Transfer the uniformly mixed material to a corundum crucible. Place the crucible in a tube furnace, open the nitrogen cylinder valve, and set the gas flow meter to allow nitrogen to flow into the quartz tube at a low flow rate. Simultaneously, open the outlet valve at the other end of the tube furnace, and purge for 10-20 minutes to remove air (oxygen) from the quartz tube, preventing the material from being oxidized or even burned at high temperatures. Increase the temperature at a rate of 5°C / min until a certain temperature (e.g., 800°C) is reached, then stop heating and hold for 60-120 minutes.

[0038] Step 140: The activated product is neutralized and the residual alkaline substances are dissolved using an acid solution for post-processing of the activated product.

[0039] In some embodiments, neutralizing the activated product with an acid solution includes: neutralizing the activated product with a hydrochloric acid solution and stirring under ventilated conditions.

[0040] In one specific embodiment, neutralizing and dissolving residual alkaline substances in the activated product with an acid solution includes: after the chemical activation treatment is completed, cooling the temperature to room temperature under nitrogen protection to obtain a precursor product. The precursor product (e.g., containing residues after the KOH reaction, such as potassium carbonate K2CO3, metallic potassium, etc.) is transferred to a beaker, an excess of HCl solution is added, and the mixture is magnetically stirred in a fume hood for several hours to neutralize and dissolve the residual alkaline substances.

[0041] Step 150: The anchoring agent is mixed with the post-treated activated product and dried to obtain the modified biomass carbon anode material.

[0042] This step can also be understood as a pre-anchoring process.

[0043] For example, the anchoring agent is selected from lithium polysulfide compounds and is used to anchor transition metal ions in an electrolyte.

[0044] In one specific embodiment, mixing and drying the anchoring agent with the post-treated activated product to obtain the modified biomass carbon anode material includes: uniformly mixing the anchoring agent with the post-treated activated product (e.g., Li2S) in a certain ratio (e.g., 1:3), and then drying it in an oven for 24 hours to obtain the carbon anode material.

[0045] In some embodiments, the method further includes applying the modified biomass carbon anode material to prepare a supercapacitor, wherein the supercapacitor includes a positive electrode, a negative electrode and an electrolyte, and the negative electrode is made by mixing the modified carbon material with a conductive agent and a binder.

[0046] This application's embodiments utilize pretreatment of biomass raw materials to remove surface stains and impurity ions, improving material purity and preventing impurities from introducing unnecessary side reactions during electrochemical processes, thereby enhancing the initial efficiency and stability of the electrode. Particle size control is achieved through sieving, ensuring the uniformity of the biomass powder, facilitating uniform processing in subsequent pyrolysis and activation steps, reducing local hot spots or structural defects, and enhancing the consistency of the final electrode material. Pyrolysis carbonization can be carried out under inert gas protection, preventing oxidation or combustion of biomass at high temperatures and maintaining the integrity of the carbon structure. A controllable heating rate ensures a stable pyrolysis process, forming a stable primary biochar framework, providing a conductive foundation for subsequent activation and avoiding pore closure or performance degradation caused by rapid heating. Chemical activation treatment can regulate pore structure and surface properties, increasing specific surface area and activity. The increased number of sites improves the transport path of ions in the electrode; optimized surface properties enhance the material's adsorption capacity for lithium ions, improving rate performance and capacity retention, while providing more loading sites for the anchoring agent; post-treatment uses acid solution to neutralize and dissolve residual alkaline substances, preventing alkaline residues from causing electrolyte decomposition or interfacial side reactions after battery assembly, ensuring the chemical stability and safety of the material; the neutralization process improves material purity, reduces interfacial impedance, and extends cycle life; pre-anchoring treatment mixes and dries the lithium polysulfide anchoring agent with the activation product, allowing the anchoring agent to undergo redox reactions with high-valence transition metal ions in the electrolyte, reducing their oxidizing properties and inhibiting excessive electrolyte decomposition and gas generation; improved negative electrode interface stability, reduced DC internal resistance, and enhanced battery safety and cycle durability.

[0047] Referring to Table 1 below, Examples 1-7 and Comparative Example 1 are set up to demonstrate the actual effect of this application.

[0048] Table 1: Results of Examples and Comparative Examples

[0049] In this embodiment, based on the method shown in Figure 1, Example 1 preferably sets the ratio of the precursor product to Li2S to be 3:1. Example 2 differs from Example 1 only in that the precursor product and Li2S are uniformly mixed at a ratio of 5:1; otherwise, they are the same as Example 1. Example 3 differs from Example 1 only in that the precursor product and Li2S are uniformly mixed at a ratio of 7:1; otherwise, they are the same as Example 1. Example 4 differs from Example 1 only in that the raw material is replaced with corn cob; otherwise, they are the same as Example 1. Example 5 differs from Example 1 only in that the raw material is replaced with corn stalk; otherwise, they are the same as Example 1. Example 6 differs from Example 1 only in that the anchoring agent Li2S is replaced with Li2S2; otherwise, they are the same as Example 1. Example 7 differs from Example 1 only in that the anchoring agent Li2S is replaced with Li2S4; otherwise, they are the same as Example 1.

[0050] The implementation process of Comparative Example 1 included: repeatedly washing the coconut shells with tap water to remove surface stains, then rinsing them 2-3 times with deionized water to reduce impurity ions; placing the washed raw materials in a forced-air drying oven and drying them at 105°C for more than 12 hours until the weight no longer changed, thus completely removing moisture; pulverizing the dried biomass raw materials into powder using a pulverizer, sieving the powder through a standard sieve, and collecting the undersize material; after pretreatment, taking an appropriate amount of the sieved biomass powder and spreading it evenly in a quartz boat, pushing the quartz boat into the center of the constant temperature zone of the quartz tube in the tubular furnace, and sealing both ends of the tubular furnace; opening the nitrogen cylinder valve, setting the gas flow meter, and allowing nitrogen to be introduced into the quartz tube at a relatively low flow rate (e.g., 100-200 mL / min). Simultaneously, open the outlet valve at the other end of the tube furnace and purge for 10-20 minutes to remove air (oxygen) from the quartz tube, preventing the material from being oxidized or even burned at high temperatures. Increase the temperature at a rate of 5°C / min until it reaches 500°C, then stop heating. Hold the temperature for 120-200 minutes. After holding, stop heating and allow the furnace to cool naturally to room temperature under continuous nitrogen purging. Turn off the nitrogen purging and carefully remove the quartz boat. At this point, you will obtain black primary biochar. Gently grind the carbonized coconut shell blocks into a fine powder in an agate mortar. Accurately weigh the biochar powder using an electronic balance. According to a specific activation ratio, weigh the corresponding mass of KOH solid. Place the coconut shell powder and KOH powder in a mortar or beaker and mix thoroughly until homogeneous. The homogeneous material is transferred to a corundum crucible, which is then placed in a tube furnace. The nitrogen cylinder valve is opened, and a gas flow meter is set to allow nitrogen to flow into the quartz tube at a low rate. Simultaneously, the outlet valve at the other end of the tube furnace is opened, and the furnace is ventilated for 10-20 minutes to remove air (oxygen) from the quartz tube and prevent the material from being oxidized or even burned at high temperatures. The temperature is increased at a rate of 5°C / min until it reaches 800°C, at which point the temperature is stopped and held for 60-120 minutes. After activation, the material is cooled to room temperature under nitrogen protection to obtain the precursor product. The precursor product (containing residues from the KOH reaction, such as potassium carbonate (K2CO3) and metallic potassium) is transferred to a beaker, and an excess of HCl solution is added. The mixture is then magnetically stirred in a fume hood for several hours to neutralize and dissolve any remaining alkaline substances.

[0051] Referring to Figure 2, in Examples 1-4, the addition of an anchoring agent significantly reduced the gas production rate after 15 days of storage, indicating that the anchoring agent effectively reduced the high oxidation state of nickel ions (Ni). 4+ The oxidizing properties of Ni are improved, thus reducing gas production during storage. As shown in Table 1, it can be seen that the DC internal resistance decreased after adding an anchoring agent to the precursor product in Examples 1-7. This is mainly because the addition of the anchoring agent reduces the Ni content. 4+ The oxidizing properties inhibit excessive decomposition of the electrolyte, thereby enabling the electrolyte decomposition products to form a uniform CEI film on the positive electrode, reducing DC internal resistance, and thus further improving the capacity retention rate.

[0052] In supercapacitors, especially when high-nickel ternary cathodes (NCM) and lithium cobalt oxide (LCO) are used as positive electrodes, the Ni in its highly oxidized state... 4+ While contributing to increased battery capacity, it also triggers a series of side effects, severely impacting battery cycle life, safety, and stability. High-oxidation-state Ni 4+ It has strong oxidizing properties and will attack and oxidize organic electrolytes. Carbonate solvents in the electrolyte (such as EC and DEC) are oxidized under high voltage, producing gases such as CO2 and CO, causing the supercapacitor to swell and, in severe cases, even explode. Ni 4+ To stabilize itself, it will oxidize adjacent lattice oxygen (O). 2- This leads to the release of oxygen, which further oxidizes the electrolyte, generating a large amount of heat and gas. 4+ It will also participate in similar side reactions, exacerbating thermal instability. This process will drastically increase the internal temperature and pressure of the supercapacitor, greatly increasing the risk of thermal runaway (fire, explosion). Electrolyte decomposition products (such as polycarbonate, Li2CO3) form a thick and uneven electrolyte interphase (CEI) film on the positive electrode surface, which hinders lithium ion transport, increases internal resistance, and leads to capacity decay and rate performance degradation.

[0053] The biomass carbon anode material prepared in this application introduces a transition metal ion anchoring agent. This anchoring agent has strong reducing properties, while high-valence transition metal ions (such as Ni)... 4+ ( ) is a strong oxidizing agent, and the two undergo a redox reaction, turning Ni into Ni 4+ Reduced to Ni 2+ Reduce Ni 4+ The oxidation of the organic electrolyte reduces gas production and improves the safety performance of the supercapacitor. Simultaneously, Li is generated. + This replenishes the lithium source and improves the capacity retention of supercapacitors. Furthermore, it reduces Ni... 4+ The oxidizing properties of the electrolyte decomposition products form a uniformly thick interfacial film at the positive electrode, preventing excessive electrolyte decomposition and resulting in an overly thick CEI film, thus improving rate performance. The chemical reaction formula is shown below: .

[0054] This application also discloses a modification system for biomass carbon anode materials. Referring to Figure 3, the system includes: a raw material pretreatment module 310, a pyrolysis carbonization treatment module 320, a chemical activation treatment module 330, a post-treatment module 340, and a material generation module 350.

[0055] For example, the raw material pretreatment module 310 is used to pretreat biomass raw materials to remove impurities and control particle size.

[0056] For example, the pyrolysis carbonization processing module 320 is used to pyrolyze the pretreated biomass raw material into biomass powder, and heat it to the carbonization temperature at a controllable heating rate under inert gas protection and hold it at the temperature to form primary biochar.

[0057] For example, the chemical activation treatment module 330 is used to perform chemical activation treatment on the primary biochar after mixing it with an activator at an activation temperature, in order to regulate the pore structure and surface properties and generate activation products.

[0058] For example, post-processing module 340 is used to neutralize and dissolve residual alkaline substances in the activated product with an acid solution for post-processing the activated product.

[0059] For example, the material generation module 350 is used to mix and dry the anchoring agent with the post-treated activation product to obtain a modified biomass carbon anode material, wherein the anchoring agent is selected from lithium polysulfide compounds and is used to anchor transition metal ions in the electrolyte.

[0060] This application also discloses a supercapacitor, which includes the supercapacitor electrolyte described above and a supercapacitor prepared using the aging process described above. Specifically, for the positive electrode, activated carbon, ternary cathode material (NCM811), conductive agent SuperP, and binder polyvinylidene fluoride (PVDF) are mixed with an appropriate amount of N-methylpyrrolidone (NMP) in a certain proportion to form a slurry, which is then coated onto aluminum foil. For the negative electrode, the biomass-based negative electrode material prepared above is mixed with SuperP, PAA, and NMP in a certain proportion to form a slurry, which is then coated onto copper foil. After drying, rolling, die-cutting, and other processes, corresponding positive and negative electrode sheets are formed. Then, the positive and negative electrode sheets and a separator are wound together, and a commercially available organic electrolyte is used to finally prepare the supercapacitor.

[0061] The biomass carbon anode material modification system disclosed in this application achieves fully controllable processing of biomass raw materials through the coordinated operation of a raw material pretreatment module, a pyrolysis carbonization module, a chemical activation module, a post-treatment module, and a material generation module. The pretreatment module ensures impurity removal and particle size uniformity, laying the foundation for subsequent steps. The pyrolysis carbonization module forms a stable biochar framework under inert gas protection, improving conductivity. The chemical activation module optimizes pore structure and surface activity, enhancing ion transport efficiency. The post-treatment module eliminates residual alkaline substances through acid neutralization, ensuring the chemical stability of the material. The material generation module introduces lithium polysulfide anchoring agents to effectively inhibit the oxidative decomposition of electrolyte by transition metal ions, thereby improving the overall cycle life, safety, and rate performance of the supercapacitor. Furthermore, the systematic design improves production efficiency and consistency.

[0062] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this application, and this application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this application, and these modifications and improvements are also considered to be within the scope of protection of this application.

Claims

1. A method for modifying biomass carbon anode materials, characterized in that, include: Pre-treating biomass raw materials to remove impurities and control particle size; pyrolyzing and carbonizing the pre-treated biomass raw materials into biomass powder, and heating to the carbonization temperature at a controllable heating rate under inert gas protection and holding at the temperature to form primary biochar; mixing the primary biochar with an activator and then chemically activating it at the activation temperature to regulate the pore structure and surface properties and generate activation products. The activated product is neutralized and residual alkaline substances are dissolved using an acid solution for post-processing. The anchoring agent is mixed with the post-treated activated product and dried to obtain a modified biomass carbon anode material, wherein the anchoring agent is selected from lithium polysulfide compounds and is used to anchor transition metal ions in the electrolyte.

2. The method according to claim 1, characterized in that, The biomass raw material is selected from one of bamboo, coconut shell, fruit shell, bagasse, corn stalk, wheat stalk, cotton stalk, rice husk, and corn cob. The pre-treatment of the biomass raw material includes: washing, drying, crushing, and sieving the biomass raw material. Washing the biomass raw material includes repeatedly rinsing the biomass raw material with tap water and / or deionized water. Drying the biomass raw material includes drying the biomass raw material at 105°C for no less than 12 hours. Sieving the biomass raw material includes collecting the undersize material through a standard sieve.

3. The method according to claim 1, characterized in that, The pyrolysis carbonization of the pretreated biomass raw material into biomass powder includes: pyrolyzing and carbonizing the pretreated biomass raw material into biomass powder based on a carbonization temperature of 500-600℃, a holding time of 120-200 minutes, and a heating rate of 5℃ / minute.

4. The method according to claim 1, characterized in that, The step of chemically activating the primary biochar with an activator at an activation temperature includes: based on the conditions of an activation temperature of 800-1000℃, a holding time of 60-120 minutes, a heating rate of 5℃ / minute, and the activator being potassium hydroxide, the primary biochar is mixed with an activator and then chemically activated at an activation temperature.

5. The method according to claim 1, characterized in that, The anchoring agent includes one or more of Li2S, Li2S2, Li2S4, Li2S6 and Li2S8.

6. The method according to claim 1, characterized in that, The step of mixing the anchoring agent with the post-treated activated product includes mixing the anchoring agent with the post-treated activated product at a mixing ratio of 1:3 to 1:

10.

7. The method according to claim 6, characterized in that, The mixing ratio is 1:3 to 1:

7.

8. The method according to claim 1, characterized in that, The neutralization of the activated product with an acid solution includes: neutralizing the activated product with hydrochloric acid solution and stirring under ventilated conditions.

9. The method according to claim 1, characterized in that, The method further includes applying the modified biomass carbon negative electrode material to prepare a supercapacitor, wherein the supercapacitor includes a positive electrode, a negative electrode and an electrolyte, and the negative electrode is made by mixing the modified carbon material with a conductive agent and a binder.

10. A modification system for biomass carbon anode materials, characterized in that, include: The raw material pretreatment module is used to pretreat biomass raw materials to remove impurities and control particle size; The pyrolysis carbonization module is used to pyrolyze and carbonize the pretreated biomass raw material into biomass powder, and to heat it to the carbonization temperature at a controllable heating rate under inert gas protection and hold it at the temperature to form primary biochar. The chemical activation module is used to mix the primary biochar with an activator and then perform chemical activation at an activation temperature to regulate the pore structure and surface properties and generate activation products. The post-processing module is used to neutralize and dissolve residual alkaline substances in the activated product using an acid solution, and is used to post-process the activated product; the material generation module is used to mix and dry the anchoring agent with the post-processed activated product to obtain a modified biomass carbon anode material, wherein the anchoring agent is selected from lithium polysulfide compounds and is used to anchor transition metal ions in the electrolyte.

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