A method for low cost mass production of carbon aerogels

Abstract

This invention discloses a low-cost, large-scale method for preparing carbon aerogels. A reaction solution is prepared by adding water-soluble resin, aldehydes, an alkaline catalyst, and distilled water to a constant-temperature water bath. A pore-forming agent, cyclodextrin, is added to the clarified reaction solution to generate a bulk aerogel, which is then pulverized and dried. The dried powder 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 activated by introducing CO2 to obtain activated carbon aerogel powder with a porous network structure. The raw materials used in this invention are abundant, inexpensive, and have low ash, pH, and heavy metal content, making them suitable for large-scale industrial production. They are particularly suitable for preparing supercapacitor electrodes, lithium-ion electrodes, and lithium-sulfur electrodes. Furthermore, they can be applied to catalyst supports, heavy metal ion adsorption, gas adsorption, and hydrogen storage materials, and have significant application value in energy storage, catalysis, adsorption, and other nanomaterials and related technologies.

Description

Technical Field

[0001] This invention belongs to the field of industrial-grade carbon aerogel powder preparation technology, specifically relating to carbon aerogels with water-soluble resin as precursors and their preparation methods. Background Technology

[0002] Carbon aerogel is a porous material with a nano-network structure, exhibiting unique properties in mechanics, acoustics, electricity, thermality, and optics. As a high-performance nano-carbon material, it is gradually showing great application potential in various sectors of the national economy. Due to its ultra-high specific surface area, reasonable pore size distribution, and easily controllable surface properties, carbon aerogel exhibits high and stable conductivity over a wide range compared to super-activated carbon as an electrode, overcoming problems such as high internal contact resistance, poor electrolyte wettability, and insufficient utilization of specific surface area. 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] The raw materials for preparing carbon aerogel powder mainly consist of expensive chemical products such as resorcinol and phloroglucinol, which greatly increases the cost of industrial production. This invention primarily uses inexpensive water-soluble resin as a raw material, and through the addition of a cross-linking agent, it gels to form a porous network structure of carbon aerogel powder.

[0004] The preparation of carbon aerogel powder mainly involves using resorcinol-formaldehyde solution as a precursor, which is dispersed, polymerized, and carbonized in an oil phase. This is a commonly used synthesis method in laboratories. However, for industrial production, the high cost of resorcinol as a precursor has become a technological bottleneck restricting its large-scale development. For example, patent document CN895770A discloses "a method for preparing carbon aerogel powder," the main feature of which is the use of resorcinol-formaldehyde as a precursor, which is dispersed in dimethyl silicone oil at low temperature under alkaline catalyst conditions, and undergoes a gel polymerization reaction 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. The bacterial cellulose slurry is mechanically pulverized at 9000-18000 rpm for 5-15 minutes to form a homogeneous slurry suspension. After being poured out, acetone is added, and the mixture is frozen at -50°C and then dried for 24-48 hours. Although the raw material is biomass, which is abundant, the ash content, pH value, and heavy metal content of the biomass raw material are difficult to control. Furthermore, the synthesis process involves mechanical pulverization at 9000-18000 rpm 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 low-cost, large-scale method for preparing carbon aerogels that 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 low-cost, large-scale method for preparing carbon aerogels 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 agent 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, and place the reactants in a water bath at a temperature of 75℃-95℃ to generate block gel.

[0009] (3) The obtained bulk gel is crushed into powder material by a pulverizer, dried at room temperature and pressure, and then dried in a drying oven at 60-80℃; the particle size of the powder material is controlled below 20μm.

[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 ratio and technical parameters of each step are controlled through synergistic optimization to obtain particles with a pore size distribution of 0.5–20 nm, an average particle size of 3–20 μm, and a specific surface area of ​​1000–2000 m². 2 / g, tap density 0.3 g / cm³ 3 ~0.6 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 final product was obtained with a pore size distribution of 0.5–20 nm, an average particle size of 4–12 μm, and a specific surface area of ​​1600–1950 m². 2 / g, tap density 0.3 g / cm³ 3 ~0.45 g / cm 3 Activated carbon aerogel powder with a porous network structure.

[0020] The method for low-cost, large-scale preparation of carbon aerogels according to the present invention, after adopting the above technical solution, has the following positive effects:

[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 activated carbon aerogel powder with a porous network structure prepared has an average particle size of 4-12 μm and a specific surface area of ​​1600-1950 m². 2 / g, tap density 0.3 g / cm³ 3 ~0.45 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 low-cost, large-scale method for preparing carbon aerogels according to the present invention, with reference to specific embodiments, is not intended to limit the scope of the invention. Based on the technical concept and embodiments of the present 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 the present invention.

[0026] Example 1

[0027] A low-cost, large-scale method for preparing carbon aerogels 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 cyclodextrin, a pore-forming agent, 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, place the reactants in a water bath at 80°C to gel into a block.

[0030] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 80°C.

[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-type atmosphere 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 5–10 μm, and the specific surface area was 1029 m². 2 / g, tap density 0.5 g / cm³ 3 .

[0033] Example 2

[0034] A low-cost, large-scale method for preparing carbon aerogels 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 cyclodextrin, a pore-forming agent, 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, place the reactants in a water bath at a certain temperature of 80°C to gel into a block.

[0037] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 60°C.

[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-type atmosphere 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 5–10 μm, and the specific surface area was 1005 m². 2 / g, tap density 0.6 g / cm³ 3 .

[0040] Example 3

[0041] A low-cost, large-scale method for preparing carbon aerogels 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, place the reactants in a water bath at a certain temperature of 75°C to gel into a block.

[0044] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 80°C.

[0045] (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 3 h, continue to raise the temperature to 1050°C at a rate of 5°C / min, hold for 1 h, and cool naturally to room temperature to obtain carbon aerogel powder;

[0046] (5) The carbon aerogel powder was added to a box-type atmosphere 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 5–10 μm, and its specific surface area was 1646 m². 2 / g, tap density 0.4 g / cm³ 3 .

[0047] Example 4

[0048] A low-cost, large-scale method for preparing carbon aerogels 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, place the reactants in a water bath at a certain temperature of 95°C to gel into a block.

[0051] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 70°C.

[0052] (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 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) The carbon aerogel powder was added to a box-type atmosphere furnace, and CO2 was introduced at a flow rate of 150 mL / min. Simultaneously, the temperature was increased to 800 °C at a rate of 10 °C / min and held for 10 h to obtain activated carbon aerogel. The average particle size of the powder was 5–10 μm, and the specific surface area was 1670 m². 2 / g, tap density 0.4 g / cm³ 3 .

[0054] Example 5

[0055] A low-cost, large-scale method for preparing carbon aerogels 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, place the reactants in a water bath at a certain temperature of 85°C to gel into blocks.

[0058] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 70°C.

[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-type atmosphere 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 5–10 μm, and its specific surface area was 1600 m². 2 / g, tap density 0.4 g / cm³ 3 .

[0061] Example 6

[0062] A low-cost, large-scale method for preparing carbon aerogels 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, place the reactants in a water bath at a certain temperature of 90°C to gel into blocks.

[0065] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 80°C.

[0066] (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 1 h, continue to raise the temperature to 1000°C at a rate of 5°C / min, hold for 3 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0067] (5) The carbon aerogel powder was added to a box-type atmosphere 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 5–10 μm, and its specific surface area was 1638 m². 2 / g, tap density 0.3 g / cm³ 3 .

[0068] Example 7

[0069] A low-cost, large-scale method for preparing carbon aerogels 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, place the reactants in a water bath at a certain temperature of 85°C to gel into a block.

[0072] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 70°C.

[0073] (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 1 h, continue to raise the temperature to 900°C at a rate of 5°C / min, hold for 2 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0074] (5) The carbon aerogel powder was added to a box-type atmosphere 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 5–10 μm, and its specific surface area was 1580 m². 2 / g, tap density 0.5 g / cm³ 3 .

[0075] Example 8

[0076] A low-cost, large-scale method for preparing carbon aerogels 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 cyclodextrin, a pore-forming agent, 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, place the reactants in a water bath at a certain temperature of 85°C to gel into a block.

[0079] (3) The obtained bulk gel was pulverized using a solid sample pulverizer, dried at room temperature and pressure, and then dried at 80°C.

[0080] (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 1 h, continue to raise the temperature to 1050°C at a rate of 5°C / min, hold for 1 h, and then cool naturally to room temperature to obtain carbon aerogel powder.

[0081] (5) The carbon aerogel powder was added to a box-type atmosphere 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 5–10 μm, and its specific surface area was 1656 m². 2 / g, tap density 0.3 g / cm³ 3 .

[0082] This invention prepares carbon aerogel powder using water-soluble resin as a precursor. The reaction raw materials are abundant and inexpensive industrial-grade chemical raw materials. 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-impurity, and low-ash activated carbon. Furthermore, compared with traditional resorcinol and phloroglucinol, they are inexpensive and suitable for large-scale industrial production.

[0083] The carbon aerogel powder prepared by the method of this invention also possesses characteristics such as high tap density, large specific surface area, high conductivity, and good coating effect on supercapacitor electrodes. This carbon aerogel powder is particularly suitable for applications 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 significant application value in energy storage, catalysis, adsorption, and other nanomaterials and related technologies.

[0084] 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 low-cost, large-scale preparation of carbon aerogels, characterized in that... The following steps are adopted: (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 stirred and clarified reaction solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1: (90-550), continue stirring until completely dissolved, and place the reactants in a water bath at a temperature of 75℃-95℃ to generate a block gel. (3) The obtained block gel is crushed into powder material by a pulverizer, dried at room temperature and pressure, and then dried in a drying oven at 60-80℃. (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 low-cost, large-scale preparation of carbon aerogels 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 low-cost, large-scale preparation of carbon aerogels 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 low-cost, large-scale preparation of carbon aerogels 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 low-cost, large-scale preparation of carbon aerogels 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 low-cost, large-scale preparation of carbon aerogels 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).