A method for preparing carbon aerogel using a water-soluble resin as a precursor

Abstract

This invention discloses a method for preparing carbon aerogel using water-soluble resin as a precursor. A reaction solution is prepared using water-soluble resin, aldehydes, an alkaline catalyst, and distilled water. Cyclodextrin, a pore-forming agent, is added to the clarified reaction solution. The reactants are then fed into a rapidly stirred oil phase, sheared into uniform micron-sized particles, and gelled at elevated temperatures to obtain a powder suspension. The suspension is centrifuged or filtered to obtain a powder, which is repeatedly washed with hot ethanol and then separated to obtain a powder material. The dried powder material is added to a carbonization furnace for carbonization to obtain carbon aerogel powder. The carbon aerogel powder is then added to a box-type atmosphere furnace and CO2 is introduced to obtain activated carbon aerogel powder with a porous network structure. This invention has the advantages of wide availability of raw materials and low production cost, making it suitable for large-scale industrial production, especially for the fabrication of supercapacitor electrodes, lithium-ion electrodes, and lithium-sulfur electrodes.

Description

Technical Field

[0001] This invention belongs to the field of industrial-grade carbon aerogel powder preparation technology, specifically involving a method for preparing carbon aerogel using water-soluble resin as a precursor. The prepared carbon aerogel can be widely used in the fabrication of supercapacitor electrodes, lithium-ion electrodes, lithium-sulfur electrodes, etc., and can also be applied to catalyst supports, heavy metal ion adsorption, gas adsorption, and hydrogen storage materials. Background Technology

[0002] Carbon aerogel is a novel porous material with high specific surface area, low density, high porosity, and excellent chemical and thermal stability. Due to its superior pore structure and electrical conductivity, it is widely used in energy storage, adsorption and separation, catalysis, polymer materials, magnetic materials, other nanomaterials, and sensors, and has broad application value in mechanics, acoustics, electricity, thermodynamics, and optics. Especially in terms of specific capacitance—a crucial indicator for supercapacitor materials—it possesses unparalleled advantages over super-activated carbon, making it an ideal electrode material for supercapacitors.

[0003] However, the raw materials for traditional porous carbon material preparation mainly consist of expensive chemical products such as resorcinol and phloroglucinol, which greatly increases the cost of industrial production. Furthermore, the production process requires the use of large quantities of chemicals, which not only increases costs but may also cause secondary pollution to the environment. In addition, ordinary porous carbon materials are difficult to effectively separate and recover after adsorption, limiting their widespread application in practice.

[0004] Furthermore, for industrial production, the high cost of resorcinol as a precursor is a technological bottleneck restricting its large-scale development. For example, patent document CN895770A discloses a "method for preparing carbon aerogel powder," whose main feature is the use of resorcinol-formaldehyde as a precursor. Under alkaline catalytic conditions, it is ultrasonically dispersed in dimethyl silicone oil at low temperature, and a gel polymerization reaction occurs under heating and ultrasonic action. The carbon aerogel powder is then obtained through separation, washing, supercritical drying, and carbonization. Patent document CN106693842A discloses a "biomass carbon aerogel and its preparation method and application," characterized by a biomass carbon aerogel based on the self-assembly of bacterial fibers. It is mechanically pulverized at 9000-18000 r / min for 5-15 min to form a homogeneous slurry suspension. After pouring out the mechanically pulverized bacterial cellulose slurry, acetone is added, and it is frozen at -50℃ and then dried for 24-48 h. Although the raw material for this patent is biomass, which is abundant, the ash content, pH value, and heavy metal content of biomass raw materials are difficult to control. Furthermore, the synthesis process involves mechanical crushing at 9000-18000 r / min and ultra-low temperature freeze drying, which greatly increases the equipment requirements for industrial production. Summary of the Invention

[0005] This invention addresses the technical challenges of high raw material prices, high costs, difficulty in controlling raw material composition, and high requirements for production equipment in the existing industrial production of carbon aerogels. It provides a method for preparing carbon aerogels using water-soluble resins as precursors, which has a wide range of raw material sources, low production costs, stable product properties, and is suitable for industrial production.

[0006] To achieve the above-mentioned objectives of this invention, a method for preparing carbon aerogel using water-soluble resin as a precursor is implemented using the following technical solution:

[0007] (1) Add water-soluble resin, aldehydes, alkaline catalyst and distilled water to a constant temperature water bath according to the set ratio and stir for 15 to 30 minutes to prepare a reaction solution. Control the temperature of the constant temperature water bath at 50℃ to 85℃. The molar ratio of water-soluble resin to aldehyde is 1:1 to 3. The molar ratio of water-soluble resin to alkaline catalyst is 1:(250 to 650).

[0008] (2) Add pore-forming cyclodextrin to the above-mentioned stirred and clarified reaction solution, wherein the molar ratio of cyclodextrin to water-soluble resin is 1: (90-550), continue stirring until completely dissolved, then feed the reactants into the oil phase substance being stirred at high speed, shear the reactants into uniform micron-sized emulsion particles, and heat up to gelatinize to obtain a powder suspension.

[0009] (3) The obtained suspension is centrifuged or filtered to obtain powdered material. The powdered material is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain powdered material. The powder is dried at room temperature and pressure and then placed in a drying oven at 60-80℃ for drying.

[0010] (4) Add the dried powder material into the carbonization furnace, evacuate at 130-180℃ and then fill with inert gas for protection, then raise the temperature to 400-600℃ at a rate of 5-10℃ / min and hold for 20-60min; continue to raise the temperature to 600-800℃ at a rate of 5-10℃ / min and hold for 2-5h; then continue to raise the temperature to 800-1100℃ at a rate of 5-10℃ / min and hold for 1-5h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0011] (5) Add carbon aerogel powder into a box furnace, introduce CO2 at a flow rate of 50-200 mL / min, and simultaneously raise the temperature to 800-1000℃ at a rate of 5-10℃ / min, and keep it at the temperature for 2-10 h to obtain activated carbon aerogel powder with a porous network structure.

[0012] Preferably, in step (1), the water-soluble resin comprises one of phenolic resin, bisphenol A type resin, and water-soluble unsaturated polyester resin SR-1.

[0013] Preferably, in step (1), the aldehydes include one of formaldehyde, acetaldehyde, propionaldehyde, and furfural.

[0014] Preferably, in step (1), the alkaline catalyst comprises one of ammonia, hexamethylenetetramine, alkali metal hydroxide, alkaline earth metal hydroxide, and sodium carbonate.

[0015] Preferably, the raw material ratios and technical parameters of each step are controlled through synergistic optimization to ultimately obtain particles with a pore size distribution of 0.5–18 nm, an average particle size of 3–17 μm, and a specific surface area of ​​1100–2000 m². 2 / g, tap density 0.3 g / cm³ 3 ~0.55 g / cm 3 Activated carbon aerogel powder with a porous network structure.

[0016] Further, in step (1), the aldehydes include one of formaldehyde, acetaldehyde, propionaldehyde, and furfural, and the alkaline catalyst includes one of ammonia, hexamethylenetetramine, alkali metal hydroxide, alkaline earth metal hydroxide, and sodium carbonate.

[0017] Furthermore, in step (1), the density of the prepared reaction solution is 0.8-1.2 g / cm³. 3 .

[0018] Further, in step (1), the molar ratio of the water-soluble resin to the alkaline catalyst is 1:(290~550), and the temperature of the constant temperature water bath is controlled in the range of 60℃~75℃; in step (2), the molar ratio of the cyclodextrin to the water-soluble resin is 1:(100~500).

[0019] Furthermore, by synergistically optimizing and controlling the raw material ratios and technical parameters at each step, a particle size distribution of 0.5–16 nm, an average particle size of 4–10 μm, and a specific surface area of ​​1700–2000 m² was finally obtained. 2 / g, tap density 0.3 g / cm³ 3 ~0.42 g / cm 3 Activated carbon aerogel powder with a porous network structure.

[0020] The method for preparing carbon aerogel using water-soluble resin as a precursor, as described in this invention, has the following positive effects after adopting the above technical solution:

[0021] (1) This invention is the first to use water-soluble resin as a precursor and prepare activated carbon aerogel powder with a porous network structure by microemulsion method. It has low production cost and is easy to carry out large-scale industrial production.

[0022] (2) The reaction raw materials used in this invention are mainly industrial-grade chemical raw materials that are abundant and inexpensive. Compared with traditional biomass raw materials, they have lower ash content, pH value and heavy metal content, which can meet the requirements of supercapacitors for high purity, low impurities and low ash content of activated carbon.

[0023] (3) Compared with resorcinol and phloroglucinol, the raw materials for preparing carbon aerogel, the price is low and the production cost of the final product is reduced by more than 25%, which is suitable for large-scale industrial production. The carbon aerogel powder prepared also has the characteristics of high tap density, large specific surface area, high conductivity, and good coating effect of supercapacitor electrode, which significantly improves the market competitiveness of the product.

[0024] (4) The prepared activated carbon aerogel powder with a porous network structure has an average particle size of 4–10 μm and a specific surface area of ​​1700–2000 m². 2 / g, tap density 0.3 g / cm³ 3 ~0.42 g / cm 3 It is particularly suitable for use in supercapacitor electrodes, lithium-ion electrodes, lithium-sulfur electrodes, etc., and can also be used as catalyst supports, heavy metal ion adsorption, gas adsorption and hydrogen storage materials. It also has important application value in energy storage, catalysis, adsorption and other nanomaterials and technology related fields. Detailed Implementation

[0025] The following detailed description of a method for preparing carbon aerogel using a water-soluble resin as a precursor, with reference to specific embodiments, is not intended to limit the scope of the invention. Based on the technical concept and embodiments of this invention, any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the invention should be included within the protection scope of this invention.

[0026] Example 1

[0027] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0028] (1) Add water-soluble phenolic resin, formaldehyde and sodium hydroxide to distilled water and stir for 30 minutes to prepare a solution with a density of 1.1 g / cm³. 3 The reaction solution was prepared and stirred in a constant temperature water bath at 60°C; the molar ratio of the water-soluble phenolic resin to formaldehyde was 1:1; the molar ratio of the water-soluble phenolic resin to sodium hydroxide was 1:500.

[0029] (2) Add pore-forming agent cyclodextrin to the above-mentioned stirred and clarified solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1:100. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0030] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 80°C for drying.

[0031] (4) Add the dried powder to the carbonization furnace, evacuate at 150°C and then fill with inert gas for protection, raise the temperature to 400°C at a rate of 5°C / min, hold for 60 min, continue to raise the temperature to 800°C at a rate of 5°C / min, hold for 2 h, continue to raise the temperature to 1000°C at a rate of 5°C / min, hold for 2 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0032] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 100 mL / min. Simultaneously, the temperature was increased to 1000 °C at a rate of 10 °C / min and held for 10 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1044 m². 2 / g, tap density 0.5 g / cm³ 3 .

[0033] Example 2

[0034] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0035] (1) Add water-soluble bisphenol A resin, formaldehyde and sodium bicarbonate to distilled water and stir for 15 minutes to prepare a solution with a density of 1.2 g / cm³. 3 The reaction solution was prepared and stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble bisphenol A resin to formaldehyde was 1:1; the molar ratio of the water-soluble bisphenol A resin to sodium bicarbonate was 1:500.

[0036] (2) Add pore-forming agent cyclodextrin to the above-mentioned stirred and clarified solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1:200. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0037] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 60°C for drying.

[0038] (4) Add the dried powder to the carbonization furnace, evacuate at 150°C and then fill with inert gas for protection, raise the temperature to 400°C at a rate of 5°C / min, hold for 60 min, continue to raise the temperature to 800°C at a rate of 5°C / min, hold for 1 h, continue to raise the temperature to 1000°C at a rate of 5°C / min, hold for 2 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0039] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 100 mL / min. Simultaneously, the temperature was increased to 1000℃ at a rate of 10℃ / min and held for 10 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1023 m². 2 / g, tap density 0.6 g / cm³ 3 .

[0040] Example 3

[0041] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0042] (1) Take water-soluble unsaturated polyester resin (SR-1), formaldehyde and sodium bicarbonate, add them to distilled water and stir for 30 minutes to prepare a solution with a density of 1.1 g / cm³. 3 The reaction solution was stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble unsaturated polyester resin (SR-1) to formaldehyde was 1:1; the molar ratio of the water-soluble unsaturated polyester resin (SR-1) to sodium bicarbonate was 1:500.

[0043] (2) Add pore-forming agent cyclodextrin to the above-mentioned stirred and clarified solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1:200. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0044] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 80°C for drying.

[0045] (4) Add the dried powder to the carbonization furnace, vacuum it at 150°C and then fill it with inert gas for protection. Heat it to 500°C at a rate of 5°C / min and hold it for 60 min. Continue to heat it to 800°C at a rate of 5°C / min and hold it for 3 h. Continue to heat it to 1050°C at a rate of 5°C / min and hold it for 1 h. Let it cool down naturally to room temperature to obtain carbon aerogel powder.

[0046] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 150 mL / min. Simultaneously, the temperature was increased to 950 °C at a rate of 10 °C / min and held for 12 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1675 m². 2 / g, tap density 0.4 g / cm³ 3 .

[0047] Example 4

[0048] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0049] (1) Add water-soluble phenolic resin, acetaldehyde and sodium hydroxide to distilled water and stir for 30 minutes to prepare a solution with a density of 0.9 g / cm³. 3 The reaction solution was prepared and stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble phenolic resin to acetaldehyde was 1:1; the molar ratio of the water-soluble phenolic resin to sodium hydroxide was 1:500.

[0050] (2) Add sucrose, a pore-forming agent, to the above-mentioned stirred and clarified solution, wherein the mass ratio of sucrose to water-soluble resin is 1:300. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0051] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 70°C for drying.

[0052] (4) Add the dried block or powder into the carbonization furnace, evacuate at 150°C and then fill with inert gas for protection, raise the temperature to 500°C at a rate of 5°C / min, hold for 60 min, continue to raise the temperature to 800°C at a rate of 5°C / min, hold for 1 h, continue to raise the temperature to 1050°C at a rate of 5°C / min, hold for 2 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0053] (5) Add the carbon aerogel block or powder into a box furnace, introduce CO2 at a flow rate of 150 mL / min, and simultaneously raise the temperature to 800℃ at a rate of 10℃ / min, hold for 10 h to obtain activated carbon aerogel. The average particle size of the powder is 5-9 μm, and the specific surface area is 1691 m². 2 / g, tap density 0.4 g / cm³ 3 .

[0054] Example 5

[0055] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0056] (1) Add water-soluble phenolic resin, furfural and potassium hydroxide to distilled water and stir for 20 minutes to prepare a solution with a density of 1.2 g / cm³. 3 The reaction solution was prepared and stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble phenolic resin to furfural was 1:2; the molar ratio of the water-soluble phenolic resin to potassium hydroxide was 1:500.

[0057] (2) Add pore-forming agent starch to the above-mentioned stirred and clarified solution, wherein the mass ratio of starch to water-soluble resin is 1:500. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0058] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 70°C for drying.

[0059] (4) Add the dried powder to the carbonization furnace, evacuate at 150°C and then fill with inert gas for protection, raise the temperature to 500°C at a rate of 5°C / min, hold for 60 min, continue to raise the temperature to 800°C at a rate of 5°C / min, hold for 2 h, continue to raise the temperature to 950°C at a rate of 5°C / min, hold for 2 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0060] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 150 mL / min. Simultaneously, the temperature was increased to 850 °C at a rate of 10 °C / min and held for 12 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1632 m². 2 / g, tap density 0.4 g / cm³ 3 .

[0061] Example 6

[0062] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0063] (1) Add water-soluble bisphenol A resin, propionaldehyde and sodium hydroxide to distilled water and stir for 20 min to prepare a solution with a density of 0.9 g / cm³. 3 The reaction solution was prepared and stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble bisphenol A resin to propionaldehyde was 1:1; the molar ratio of the water-soluble bisphenol A resin to sodium hydroxide was 1:500.

[0064] (2) Add pore-forming agent starch to the above-mentioned stirred and clarified solution, wherein the mass ratio of starch to water-soluble resin is 1:500. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0065] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 80°C for drying.

[0066] (4) Add the dried powder to the carbonization furnace, vacuum it at 150°C and then fill it with inert gas for protection. Heat it to 500°C at a rate of 5°C / min and hold it for 60 min. Continue to heat it to 800°C at a rate of 5°C / min and hold it for 1 h. Continue to heat it to 1000°C at a rate of 5°C / min and hold it for 3 h. Let it cool down naturally to room temperature to obtain carbon aerogel powder.

[0067] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 100 mL / min. Simultaneously, the temperature was increased to 900 °C at a rate of 10 °C / min and held for 12 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1662 m². 2 / g, tap density 0.3 g / cm³ 3 .

[0068] Example 7

[0069] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0070] (1) Take water-soluble unsaturated polyester resin (SR-1), acetaldehyde and sodium bicarbonate, add them to distilled water and stir for 20 minutes to prepare a solution with a density of 1.0 g / cm³. 3 The reaction solution was stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble unsaturated polyester resin (SR-1) to acetaldehyde was 1:3; the molar ratio of the water-soluble unsaturated polyester resin (SR-1) to sodium bicarbonate was 1:300.

[0071] (2) Add sucrose, a pore-forming agent, to the above-mentioned stirred and clarified solution, wherein the mass ratio of sucrose to water-soluble resin is 1:400. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0072] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 70°C for drying.

[0073] (4) Add the dried powder to the carbonization furnace, vacuum it at 150°C and then fill it with inert gas for protection. Heat it to 500°C at a rate of 5°C / min and hold it for 60 min. Continue to heat it to 800°C at a rate of 5°C / min and hold it for 1 h. Continue to heat it to 900°C at a rate of 5°C / min and hold it for 2 h. Let it cool down to room temperature naturally to obtain carbon aerogel powder.

[0074] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 150 mL / min. Simultaneously, the temperature was increased to 950 °C at a rate of 10 °C / min and held for 11 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1603 m². 2 / g, tap density 0.5 g / cm³ 3 .

[0075] Example 8

[0076] A method for preparing carbon aerogel using a water-soluble resin as a precursor includes the following steps:

[0077] (1) Add water-soluble phenolic resin, acetaldehyde and hexamethylenetetramine to distilled water and stir for 15 minutes to prepare a solution with a density of 1.1 g / cm³. 3 The reaction solution was prepared and stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble phenolic resin to acetaldehyde was 1:1; the molar ratio of the water-soluble phenolic resin to hexamethylenetetramine was 1:300.

[0078] (2) Add pore-forming agent cyclodextrin to the above-mentioned stirred and clarified solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1:200. After stirring until completely dissolved, drop the reactants into the oil phase substance being stirred at high speed, shear them into uniform micron-sized emulsion particles, and heat to gel to obtain a powder suspension.

[0079] (3) The obtained suspension is centrifuged or filtered to obtain a powder. The powder is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain a powder. The powder is dried at room temperature and pressure, and then heated to 80°C for drying.

[0080] (4) Add the dried powder to the carbonization furnace, vacuum it at 150°C and then fill it with inert gas for protection. Heat it to 500°C at a rate of 5°C / min and hold it for 60 min. Continue to heat it to 800°C at a rate of 5°C / min and hold it for 1 h. Continue to heat it to 1050°C at a rate of 5°C / min and hold it for 1 h. Let it cool down to room temperature naturally to obtain carbon aerogel powder.

[0081] (5) The carbon aerogel powder was added to a box furnace, and CO2 was introduced at a flow rate of 100 mL / min. Simultaneously, the temperature was increased to 900 °C at a rate of 10 °C / min and held for 10 h to obtain activated carbon aerogel powder. The average particle size of this powder was 5–9 μm, and its specific surface area was 1685 m². 2 / g, tap density 0.3 g / cm³ 3 .

[0082] This invention prepares carbon aerogel powder using water-soluble resin as a precursor, primarily employing a combination of sol-gel and microemulsion technologies. The reaction raw materials are mainly abundant and inexpensive industrial-grade chemical raw materials, which, compared to traditional biomass raw materials, have lower ash content, pH value, and heavy metal content, meeting the requirements of supercapacitors for high-purity, low-impurity, and low-ash activated carbon. Furthermore, compared to traditional resorcinol and phloroglucinol, they are inexpensive and suitable for large-scale industrial production. This invention allows for the preparation of reaction solutions with different concentrations, selection of appropriate catalysts, and appropriate types and amounts of surfactants, dispersing the reaction solution into an oil phase with a density comparable to that of an aqueous solution at different stirring rates to form microemulsion particles. By controlling appropriate temperature and time, micron-sized organic aerogel powder is formed. Through separation, carbonization, and activation, carbon aerogel powders with different theoretical densities and specific surface areas are obtained. The prepared carbon aerogel powder also exhibits high tap density, large specific surface area, high conductivity, and good coating effect on supercapacitor electrodes. This carbon aerogel powder is particularly suitable for use in supercapacitor electrodes, lithium-ion electrodes, lithium-sulfur electrodes, etc. It can also be used as a catalyst support, heavy metal ion adsorption, gas adsorption and hydrogen storage material. It also has important application value in energy storage, catalysis, adsorption and other nanomaterials and technology related fields.

[0083] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention, and those skilled in the art can easily make other modifications. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein. To describe the present invention, a method for the continuous preparation of carbon aerogel precursors according to the present invention will be further described in detail below with reference to embodiments. However, the present invention is not limited to the embodiments.

Claims

1. A method for preparing carbon aerogel using water-soluble resin as a precursor, characterized in that... The following steps are to be taken: (1) Add water-soluble resin, aldehydes, alkaline catalyst, and distilled water to a constant temperature water bath according to the set ratio and stir for 15-30 minutes to prepare a reaction solution. Control the temperature of the constant temperature water bath at 50℃-85℃. The molar ratio of the water-soluble resin to the aldehyde is 1:1-3. The molar ratio of the water-soluble resin to the alkaline catalyst is 1:(250-650). The water-soluble resin includes one of phenolic resin, bisphenol A type resin, and water-soluble unsaturated polyester resin SR-1. (2) Add pore-forming agent cyclodextrin to the above-mentioned stirred and clarified reaction solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1: (90-550), continue stirring until completely dissolved, then feed the reactants into the oil phase substance being stirred at high speed, shear the reactants into uniform micron-sized emulsion particles, and raise the temperature to gelatinize to obtain a powder suspension. (3) The obtained suspension is centrifuged or filtered to obtain powdered material. The powdered material is repeatedly washed with hot ethanol, and then centrifuged or filtered to obtain powdered material. The powder is dried at room temperature and pressure and then placed in a drying oven at 60-80℃ for drying. (4) Add the dried powder material into the carbonization furnace, evacuate at 130-180℃ and then fill with inert gas for protection, then raise the temperature to 400-600℃ at a rate of 5-10℃ / min and hold for 20-60min; continue to raise the temperature to 600-800℃ at a rate of 5-10℃ / min and hold for 2-5h; then continue to raise the temperature to 800-1100℃ at a rate of 5-10℃ / min and hold for 1-5h, and then cool naturally to room temperature to obtain carbon aerogel powder. (5) Add carbon aerogel powder into a box furnace, introduce CO2 at a flow rate of 50-200 mL / min, and simultaneously raise the temperature to 800-1000℃ at a rate of 5-10℃ / min, and keep it at the temperature for 2-10 h to obtain activated carbon aerogel powder with a porous network structure.

2. The method for preparing carbon aerogel using water-soluble resin as a precursor as described in claim 1, characterized in that: In step (1), the aldehydes include one of formaldehyde, acetaldehyde, propionaldehyde, and furfural.

3. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 1, characterized in that: In step (1), the alkaline catalyst comprises one of ammonia, hexamethylenetetramine, alkali metal hydroxide, alkaline earth metal hydroxide, and sodium carbonate.

4. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 3, characterized in that: In step (1), the aldehydes include one of formaldehyde, acetaldehyde, propionaldehyde, and furfural.

5. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 4, characterized in that: In step (1), the density of the prepared reaction solution is 0.8-1.2 g / cm³. 3 .

6. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 5, characterized in that: In step (1), the molar ratio of the water-soluble resin to the alkaline catalyst is 1:(290-550), and the temperature of the constant temperature water bath is controlled within the range of 60℃-75℃; in step (2), the mass ratio of the cyclodextrin to the water-soluble resin is 1:(100-500).