A type of pine capacitor carbon, its preparation method and application

Abstract

The application discloses a kind of rigid pine capacitive carbon and its preparation method and application, the method includes the following steps: the bark of rigid pine is removed, then is crushed into 20-40 mesh sawdust, basic solution is added to the sawdust, reaction treatment, then the reaction product is solid-liquid separation, washing and drying, to obtain pretreated rigid pine particles;The pretreated rigid pine particles are placed in a fluidized bed reactor, and gas is introduced for activation, while spraying an auxiliary agent, to obtain rigid pine porous carbon;Cooling gas N2 is added to the fluidized bed reactor to reduce the temperature in the reactor, and after cooling, the rigid pine porous carbon is separated and collected;The collected rigid pine porous carbon is further ground into fine powder, and sieved to obtain capacitive carbon particles with a suitable particle size.The present application uses biomass rigid pine with high lignocellulose content as raw material, and the cellulose and hemicellulose in lignocellulose help to form more pores, while lignin helps to synthesize graphite-like carbon to improve electrical conductivity.

Description

Technical Field

[0001] This invention relates to the field of capacitor carbon technology, specifically to a type of Gangsong capacitor carbon, its preparation method, and its applications. Background Technology

[0002] With increasing fossil fuel consumption and dwindling reserves, energy sustainability has become a major global concern. Driven by environmental and usage demands, the development of environmentally friendly and inexpensive renewable energy systems, such as wind, solar, fuel cells, and tidal power, has become particularly important. However, the intermittent but continuous energy supply of these systems requires an efficient and practical storage system to ensure safe and continuous power harvesting. Supercapacitors have attracted widespread attention due to their advantages such as long cycle life, fast charge and discharge rates, high power density, and adaptability to harsh environmental conditions. However, supercapacitors are not without their drawbacks; their only major drawback is low energy density. Therefore, developing an advanced porous carbon electrode material has become a top priority in supercapacitor research.

[0003] As an abundant and renewable natural resource, wood has gradually become a research and application hotspot for capacitive carbon in recent years. Compared with traditional coal or coconut shells, wood is cheaper, more abundant, and sustainable. Its unique organic structure gives wood-based capacitive carbon excellent potential in terms of pore structure and specific surface area. In addition, the raw material processing of wood-based capacitive carbon is simple and environmentally friendly, thus possessing great market application prospects.

[0004] Pine has unique advantages as a material for capacitor charcoal. Pine wood has a low density, typically between 0.4-0.6 g / cm³. 3 This lower density makes it lighter than other woods such as oak and walnut. The lower density means that it's easier to generate carbon materials with a larger specific surface area when manufacturing capacitor carbon. Compared to some other pine species, *Pinus koraiensis* has a lower resin content. Resin can produce unstable byproducts during carbonization, affecting the electrochemical performance of the final carbon material. The lower resin content of *Pinus koraiensis* makes its carbonization process more stable, contributing to obtaining capacitor carbon with higher purity and better electrical performance. Furthermore, the natural and relatively regular pore structure of *Pinus koraiensis* helps retain a certain amount of micropores and mesopores during capacitor carbon preparation, which enhances its charge storage capacity.

[0005] Currently, traditional methods for preparing capacitor carbon mainly include physical activation, chemical activation, and direct carbonization. These methods generally use natural organic materials such as coal, coconut shells, and wood as raw materials, achieving carbonization and activation through high-temperature treatment and specific chemical reactions. However, these preparation methods often have the following problems: high energy consumption, as traditional carbonization and activation processes usually require high temperatures and long processing times. High energy consumption not only increases production costs but also puts significant pressure on the environment; uneven reaction, as some traditional methods (such as tubular furnace carbonization and activation) often suffer from uneven heat conduction and unstable reaction processes, leading to uneven product quality and difficulty in controlling pore structure; low resource utilization, as raw materials such as wood in traditional preparation methods usually require long carbonization and activation processes, and the quality and structure of the carbonized products may not be fully suitable for the requirements of high-performance capacitors, resulting in low utilization efficiency of resources such as wood; and environmental problems, as some traditional preparation methods (such as chemical activation) release toxic gases and harmful waste during production, causing environmental pollution.

[0006] Therefore, how to improve the production efficiency of capacitor carbon, reduce energy consumption, improve its electrochemical performance, and maximize the utilization of resources has become a research hotspot in the current capacitor carbon preparation technology. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a pine capacitor carbon, its preparation method and application, and to solve the technical problems of low production efficiency, high energy consumption and poor electrochemical performance of capacitor carbon.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention proposes a method for preparing briquetted capacitor carbon, comprising the following steps:

[0010] S1. Pretreatment of Pine Wood: Remove the bark from the pine wood, then crush it into 20-40 mesh wood chips. Add an alkaline solution to the wood chips and react them. Then, separate the solid and liquid components of the reaction product, wash and dry it to obtain pretreated pine wood particles.

[0011] S2. Activation: The pretreated Gangsong particles are placed into a fluidized bed reactor, gas is introduced for activation, and additives are sprayed at the same time to obtain Gangsong porous carbon.

[0012] S3. Separation and Collection: Cooling gas N2 is added to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, the porous carbon is separated and collected.

[0013] S4. Grinding and sieving: The collected porous carbon is further ground into fine powder and sieved to obtain capacitor carbon particles of suitable particle size.

[0014] Fluidized bed reactors, as a novel reactor technology, possess highly efficient and uniform heat transfer and material mixing capabilities, thus finding wide application in many high-temperature and gas-solid reactions. Fluidized bed reactors suspend solid particles through high-speed gas flow, causing the particles to behave like fluids within the reactor. This "fluidized" state enables rapid heating and uniform reaction of materials, thereby significantly improving reaction efficiency.

[0015] The advantages of fluidized bed reactors include:

[0016] Uniform heating and efficient reaction: The particles in the fluidized bed are uniformly distributed and continuously move with the airflow, maintaining stable temperature and atmosphere conditions inside the reactor, thus achieving uniform heating and effective activation of the material. This helps improve the pore structure and electrochemical performance of wood-based electrolytic carbon.

[0017] Shorter reaction time: Due to the good thermal conductivity of the fluidized bed reactor, the raw materials can reach the required reaction temperature in a shorter time, reducing reaction time and energy consumption.

[0018] Highly efficient gas-solid contact: The design of the fluidized bed reactor allows for more thorough contact between the gas and solid particles, which helps improve the reaction efficiency between the reactants in the gas and the solid raw materials, thereby enhancing the quality and performance of the capacitor carbon.

[0019] Environmental friendliness: Fluidized bed reactors can avoid the generation of harmful gases by precisely controlling the atmosphere (such as using inert gases or activating gases such as nitrogen and carbon dioxide), and the waste gases generated during the reaction process can also be effectively treated by gas recovery devices, reducing environmental pollution.

[0020] High adaptability to raw materials: Fluidized bed technology can process a variety of raw materials, including wood, plant fibers, agricultural waste, etc., and has good adaptability to raw materials. Especially when processing biomass raw materials such as wood, it can better preserve the natural structure of the raw materials and improve the specific surface area and electrochemical performance of the carbon.

[0021] Therefore, using a fluidized bed reactor for wood carbonization can produce high-quality wood-based capacitive char in a short time, with low energy consumption and high resource utilization. The use of a fluidized bed reactor for wood-based capacitive char preparation has significant technological advantages, not only improving the efficiency and performance of capacitive char preparation but also fully utilizing biomass resources such as wood, thus promoting green and sustainable development.

[0022] Preferably, in step S1, the drying is blower drying, the drying temperature is 80-100°C, the drying is slow heating drying, and the heating rate is 5-10°C / min.

[0023] Preferably, in step S1, the alkaline solution is a sodium carbonate solution or a potassium carbonate solution, and the mass concentration of the alkaline solution is 10% to 15%.

[0024] Preferably, in step S2, the auxiliary agent is a mixed solution of copper chloride and lead nitrate, wherein the mass concentration of the copper chloride solution is 10-20% and the mass concentration of the lead nitrate solution is 5-10%.

[0025] Preferably, in step S2, the activation time is 2 to 6 hours and the activation temperature is 800 to 900°C.

[0026] Preferably, in step S2, the gas is at least one of CO2 and water vapor, and the gas flow rate is 0.2–1.5 m / s. Under these gas atmospheres, Gangsong can complete the activation and pore-forming process to obtain porous carbon materials with high specific surface area.

[0027] When the gas is a mixture of CO2 and water vapor, the volume ratio of CO2 to water vapor is 1:1.

[0028] Preferably, in step S3, a cyclone separator is used to separate and collect the porous carbon.

[0029] Preferably, in step S4, the particle size of the capacitor carbon particles is 6-8 μm.

[0030] The present invention also proposes a rigid capacitor carbon, which is prepared by the rigid capacitor carbon preparation method described above.

[0031] This invention further proposes an application of rigid carbon capacitors for use as electrode materials in supercapacitors.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention selects biomass pine with high lignocellulose content as raw material. The cellulose and hemicellulose in lignocellulose help to form more pores, while lignin helps to synthesize graphitized carbon to improve conductivity.

[0034] (2) This invention selects a fluidized bed as the reactor, which has advantages such as high heat and mass transfer efficiency, uniform bed temperature, and reduced energy consumption compared with traditional tubular reactors. This helps to improve the pore structure and electrochemical performance of supercapacitor carbon. The fluid dynamic environment and physical activation process of the fluidized bed reactor work together to more accurately control the formation and development of the pore structure of carbon materials. By adjusting the operating parameters of the reactor, such as temperature, gas flow rate, residence time, etc., the proportion and size of micropores, mesopores and other pores of carbon materials can be controlled to meet the requirements of supercapacitors for electrode materials.

[0035] (3) The preparation method of Gangsong capacitor carbon provided by the present invention is simple and easy to operate. The biomass Gangsong raw material is first crushed, and then an alkaline solution is added and slowly heated and dried for pretreatment. This can maintain the integrity of the pore and channel structure in Gangsong particles. Then, high temperature gas is introduced for activation, and a mixed solution of activation aids copper chloride and lead nitrate is sprayed. This aid can be converted into copper oxide and lead oxide at high temperature, which can support the carbon skeleton and form pores. During the high temperature activation and carbonization process, it prevents shrinkage and collapse. When used as a supercapacitor electrode material, lead oxide can undergo a reversible redox reaction to store energy, thereby increasing the total capacitance of Gangsong capacitor carbon. Finally, through separation, collection and grinding and sieving operations, capacitor carbon with large specific surface area and excellent electrical performance can be prepared. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart of the preparation method of the Gangsong capacitor carbon provided by the present invention. Detailed Implementation

[0037] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0038] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0039] Example 1

[0040] A method for preparing pine capacitor carbon includes the following steps:

[0041] (1) Remove the bark from the pine wood, then crush it into 30-mesh sawdust, add sodium carbonate solution to the sawdust, react and treat it, then separate the solid and liquid of the reaction product, wash it, and dry it at a rate of 6℃ / min to 90℃ to obtain pretreated pine granules.

[0042] (2) The pretreated granulated steel particles are placed in a fluidized bed reactor and activated by introducing CO2 gas. Simultaneously, a mixed solution of copper chloride and lead nitrate is sprayed. The mass concentration of the copper chloride solution is 10%, and the mass concentration of the lead nitrate solution is 20%. The gas flow rate is controlled at 2 m³ / s. 3 The gas heating switch is turned on to make the raw materials in the bed boil and mix them for 2 hours. After the mixture is evenly mixed, the gas heating switch is turned on to make the inlet hot air temperature 850℃ and keep the bed boiling for 6 hours to obtain Gangsong porous carbon.

[0043] (3) Add cooling gas N2 to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, separate and collect the porous carbon.

[0044] (4) The collected Gangsong porous carbon is further ground into fine powder, sieved, and capacitor carbon particles with a particle size of 7μm are obtained.

[0045] Example 2

[0046] A method for preparing pine capacitor carbon includes the following steps:

[0047] (1) Remove the bark from the pine wood, then crush it into 20-mesh sawdust, add potassium carbonate solution to the sawdust, react and treat it, then separate the solid and liquid of the reaction product, wash it, and dry it at a rate of 5℃ / min to 80℃ to obtain pretreated pine granules.

[0048] (2) The pretreated granulated steel particles are placed in a fluidized bed reactor and activated by steam. Simultaneously, a mixed solution of copper chloride and lead nitrate is sprayed. The mass concentration of the copper chloride solution is 15%, and the mass concentration of the lead nitrate solution is 8%. The gas flow rate is controlled at 2 m³ / s. 3 The gas heating switch is turned on at a speed of 800℃ to bring the raw materials in the bed to a boiling state. After mixing for 2 hours, the mixture is homogeneous. Then the gas heating switch is turned on to bring the inlet hot air temperature to 800℃ and the bed is kept in a boiling state for 6 hours to obtain Gangsong porous carbon.

[0049] (3) Add cooling gas N2 to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, separate and collect the porous carbon.

[0050] (4) The collected Gangsong porous carbon is further ground into fine powder, sieved, and capacitor carbon particles with a particle size of 7μm are obtained.

[0051] Example 3

[0052] A method for preparing pine capacitor carbon includes the following steps:

[0053] (1) Remove the bark from the pine wood, then crush it into 40-mesh sawdust, add sodium carbonate solution to the sawdust, react and treat it, then separate the solid and liquid of the reaction product, wash it, and dry it at a rate of 10℃ / min to 100℃ to obtain pretreated pine granules.

[0054] (2) The pretreated granulated steel particles are placed in a fluidized bed reactor and activated by introducing a mixture of CO2 and water vapor at a volume ratio of 1:1. Simultaneously, a mixed solution of copper chloride and lead nitrate is sprayed, with the copper chloride solution having a mass concentration of 20% and the lead nitrate solution a mass concentration of 10%. The gas flow rate is controlled at 2 m³ / s. 3 The gas heating switch is turned on to make the raw materials in the bed boil and mix them for 2 hours. After the mixture is evenly mixed, the gas heating switch is turned on to make the inlet hot air temperature 900℃ and keep the bed boiling for 6 hours to obtain Gangsong porous carbon.

[0055] (3) Add cooling gas N2 to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, separate and collect the porous carbon.

[0056] (4) The collected Gangsong porous carbon is further ground into fine powder, sieved, and capacitor carbon particles with a particle size of 7μm are obtained.

[0057] Comparative Example 1

[0058] A method for preparing pine capacitor carbon includes the following steps:

[0059] (1) Remove the bark from the pine wood, then crush it into 30-mesh sawdust, add sodium carbonate solution to the sawdust, react and treat it, then separate the solid and liquid of the reaction product, wash it, and dry it at a rate of 6℃ / min to 90℃ to obtain pretreated pine granules.

[0060] (2) The pretreated granulated steel particles are placed in a fluidized bed reactor, air is introduced, and a mixed solution of copper chloride and lead nitrate is sprayed simultaneously. The mass concentration of the copper chloride solution is 15%, and the mass concentration of the lead nitrate solution is 8%. The gas flow rate is controlled at 2 m³ / s. 3 The gas heating switch is turned on to make the raw materials in the bed boil and mix them for 2 hours. After the mixture is evenly mixed, the gas heating switch is turned on to make the inlet hot air temperature 850℃ and keep the bed boiling for 6 hours to obtain Gangsong porous carbon.

[0061] (3) Add cooling gas N2 to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, separate and collect the porous carbon.

[0062] (4) The collected Gangsong porous carbon is further ground into fine powder, sieved, and capacitor carbon particles with a particle size of 7μm are obtained.

[0063] Compared with Example 1, in Comparative Example 1, the gas introduced in step (2) is air.

[0064] Comparative Example 2

[0065] A method for preparing pine capacitor carbon includes the following steps:

[0066] (1) Remove the bark from the pine wood, then crush it into 30-mesh sawdust, then perform solid-liquid separation and washing, and dry it at a rate of 6℃ / min to 90℃ to obtain pretreated pine wood particles;

[0067] (2) The pretreated granulated steel particles are placed in a fluidized bed reactor and activated by introducing CO2 gas. Simultaneously, a mixed solution of copper chloride and lead nitrate is sprayed. The mass concentration of the copper chloride solution is 15%, and the mass concentration of the lead nitrate solution is 8%. The gas flow rate is controlled at 2 m³ / s. 3The gas heating switch is turned on to make the raw materials in the bed boil and mix them for 2 hours. After the mixture is evenly mixed, the gas heating switch is turned on to make the inlet hot air temperature 850℃ and keep the bed boiling for 6 hours to obtain Gangsong porous carbon.

[0068] (3) Add cooling gas N2 to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, separate and collect the porous carbon.

[0069] (4) The collected Gangsong porous carbon is further ground into fine powder, sieved, and capacitor carbon particles with a particle size of 7μm are obtained.

[0070] Compared with Example 1, in Comparative Example 2, the sawdust was not reacted with an alkaline solution in step (1).

[0071] Comparative Example 3

[0072] A method for preparing pine capacitor carbon includes the following steps:

[0073] (1) Remove the bark from the pine wood, then crush it into 30-mesh sawdust, add sodium carbonate solution to the sawdust, react and treat it, then separate the solid and liquid of the reaction product, wash it, and dry it at a rate of 6℃ / min to 90℃ to obtain pretreated pine granules.

[0074] (2) The pretreated loose granules are placed into a fluidized bed reactor, and CO2 gas is introduced for activation, with the gas flow rate controlled at 2 m³ / min. 3 The gas heating switch is turned on to make the raw materials in the bed boil and mix them for 2 hours. After the mixture is evenly mixed, the gas heating switch is turned on to make the inlet hot air temperature 850℃ and keep the bed boiling for 6 hours to obtain Gangsong porous carbon.

[0075] (3) Add cooling gas N2 to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, separate and collect the porous carbon.

[0076] (4) The collected Gangsong porous carbon is further ground into fine powder, sieved, and capacitor carbon particles with a particle size of 7μm are obtained.

[0077] Compared with Example 1, Comparative Example 3 did not have a spraying agent in step (2).

[0078] Test methods and results

[0079] Electrochemical performance evaluation: Electrochemical tests were conducted on an electrochemical workstation (Wuhan KAST). All tests used a three-electrode system. The working electrode preparation process is as follows: The Gangsong capacitor carbon prepared in Examples 1-3 and Comparative Examples 1-3 was mixed with a conductive agent (acetylene black) and a binder (polytetrafluoroethylene) in a mass ratio of 8:1:1. An appropriate amount of NMP (N-methylpyrrolidone) was added, and the mixture was stirred for 12 hours. The mixture was then applied to the current collector, with a coating area of ​​1 cm². 2 Using a platinum sheet as the counter electrode and an Hg / HgO electrode as the reference electrode, the prepared electrode sheet was used as the working electrode. The six electrodes were immersed in 6M KOH electrolyte for constant current charge-discharge and cyclic voltammetry tests. The results are shown in Table 1 below.

[0080] Table 1 Electrode performance test results

[0081]

[0082] As shown in Examples 1-3 and Comparative Example 1, water vapor reacts with carbon via a redox reaction to primarily produce carbon monoxide (CO) and hydrogen, leading to the formation of more mesopores and macropores. Carbon dioxide reacts with carbon via a redox reaction to primarily produce carbon monoxide (CO) and carbon dioxide (CO2), often forming more micropores and mesopores. The activation by a mixed gas of CO2 and H2O combines the advantages of both, typically producing materials with different pore size distributions under different reaction conditions. The synergistic effect of these two reactions usually leads to a further increase in specific surface area and micropore ratio, resulting in higher electrochemical performance. Compared to Comparative Examples 1-3, the Gangsong capacitor carbon prepared in Examples 1-3 of this invention, when used as the working electrode, exhibits superior electrochemical performance.

[0083] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A method for producing a rigidly loose capacitive carbon, characterized by, Includes the following steps: S1. Pretreatment of Pine Wood: Remove the bark from the Pine Wood, then crush it into 20-40 mesh wood chips. Add an alkaline solution to the wood chips and react them. Then, separate the solid and liquid components of the reaction product, wash and dry it to obtain pretreated Pine Wood granules. S2. Activation: The pretreated Gangsong particles are placed into a fluidized bed reactor, gas is introduced for activation, and additives are sprayed at the same time to obtain Gangsong porous carbon. S3. Separation and Collection: Cooling gas N2 is added to the fluidized bed reactor to reduce the temperature inside the reactor. After cooling, the porous carbon is separated and collected. S4. Grinding and sieving: The collected porous carbon is further ground into fine powder and sieved to obtain capacitor carbon particles of suitable particle size. In step S1, the alkaline solution is a sodium carbonate solution or a potassium carbonate solution, and the mass concentration of the alkaline solution is 10%~15%. In step S2, the auxiliary agent is a mixed solution of copper chloride and lead nitrate, wherein the mass concentration of the copper chloride solution is 10-20% and the mass concentration of the lead nitrate solution is 5-10%. In step S2, the gas is at least one of CO2 and water vapor, and the gas flow rate is 0.2~1.5m / s.

2. The method of claim 1, wherein the rigid-flexible capacitive carbon is prepared by the steps of: In step S1, the drying is performed by forced air drying, the drying temperature is 80~100℃, the drying is performed by slow heating, and the heating rate is 5~10℃ / min.

3. The method of claim 1, wherein the rigid-flexible capacitive carbon is prepared by the steps of: In step S2, the activation time is 2-6 hours and the activation temperature is 800-900℃.

4. The method of claim 1, wherein the rigid-flexible capacitive carbon is prepared by the steps of: In step S3, a cyclone separator is used to separate and collect the porous carbon from the Gangsong material.

5. The method of claim 1, wherein the rigid-flexible capacitive carbon is prepared by the steps of: In step S4, the particle size of the capacitor carbon particles is 6~8μm.

6. A rigid polyporous carbon capacitor, characterized by, It is prepared by the method for preparing Gangsong capacitor carbon as described in any one of claims 1 to 5.

7. Use of the rigid and flexible capacitive carbon of claim 6, characterized in that, Used as electrode material for supercapacitors.

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