Method for preparing carbon aerogel by using water-soluble resin as precursor

Abstract

The invention discloses a method for preparing carbon aerogel by taking water-soluble resin as a precursor, which comprises the following steps: preparing a reaction solution from the water-soluble resin, aldehydes, a basic catalyst and distilled water, adding a pore-forming agent cyclodextrin into the reaction solution which is stirred to be clarified, and uniformly stirring; feeding reactants into an oil-phase substance which is stirred at a high speed, shearing the reactants into uniform micron-sized emulsion particles, and heating and gelling the micron-sized emulsion particles to obtain a powdery substance suspension; centrifuging the turbid liquid or carrying out suction filtration separation to obtain a powdery substance, repeatedly cleaning the powdery substance with hot ethanol, then separating to obtain a powder material, adding the dried powder material into a carbonization furnace, and carbonizing to obtain carbon aerogel powder; and adding the carbon aerogel powder into a box-type atmosphere furnace, and introducing CO2 to obtain the activated carbon aerogel powder with a porous network structure. The method has the advantages of wide raw material source and low production cost, is suitable for large-scale industrial production, and is particularly suitable for manufacturing supercapacitor electrodes, lithium ion electrodes, lithium sulfur electrodes and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of industrial-grade carbon aerogel powder preparation, and particularly relates to a method for preparing carbon aerogel by using water-soluble resin as a precursor. The prepared carbon aerogel can be widely used for making supercapacitor electrodes, lithium ion electrodes, lithium-sulfur electrodes, and the like, and can also be applied to catalyst carriers, heavy metal ion adsorption, gas adsorption, and hydrogen storage materials. BACKGROUND

[0002] Carbon aerogel is a new type of porous material with high specific surface area, low density, high porosity, excellent chemical stability and thermal stability. Due to its excellent void structure and electrical conductivity, it is widely used in energy storage, adsorption separation, catalysis, polymer materials, magnetic materials, other nanomaterials, and sensors, and has broad application value in mechanics, acoustics, electricity, heat, and optics. In particular, in the important indicator of supercapacitor material-specific capacitance, it has incomparable advantages over super-activated carbon and is an ideal electrode material for supercapacitors.

[0003] However, the traditional porous carbon material preparation raw material is mainly based on resorcinol, phloroglucinol and other high-priced chemical products, which greatly increases the cost of industrial production. In addition, a large amount of chemicals are used in the production process, which not only increases the cost, but also may cause secondary pollution to the environment. In addition, ordinary porous carbon materials are difficult to separate and recover effectively after adsorption, which limits their popularization in practical application.

[0004] In addition, for industrial production, resorcinol as a precursor, the cost of raw materials is high, which becomes a technical bottleneck restricting its large-scale development. For example, patent document CN895770A discloses a method for preparing carbon aerogel powder, which mainly uses resorcinol-formaldehyde as a precursor, disperses in dimethyl silicone oil at low temperature under the condition of alkaline catalyst, and occurs gel polymerization reaction under the action of heating and ultrasonic wave. Carbon aerogel powder is obtained by separation, washing, supercritical drying and carbonization. Patent document CN106693842A discloses a biomass carbon aerogel and its preparation method and application, which is characterized by a biomass carbon aerogel self-assembled based on bacterial fibers. The bacterial cellulose slurry is mechanically pulverized at a speed of 9000-18000 r / min for 5-15 min to form a uniform slurry suspension. After the mechanical pulverization of the bacterial cellulose slurry, add acetone, freeze at-50℃, and dry for 24-48h. Although the raw material of this patent is biomass, which is abundant in source, but the ash content, pH value and heavy metal content of the biomass raw material are difficult to control, and the mechanical pulverization at a speed of 9000-18000 r / min and the ultra-low temperature freeze drying in the synthesis process greatly increase the equipment requirements of industrial production. SUMMARY

[0005] The present application is directed to the technical problems of expensive raw materials, high cost, difficult control of raw material composition and high requirement of production equipment in the existing industrial production of carbon aerogel, and provides a method for preparing carbon aerogel with water-soluble resin as a precursor, which has wide raw material sources, low production cost, stable product properties and is suitable for industrial production.

[0006] To achieve the above-mentioned objects of the present application, the method for preparing carbon aerogel with water-soluble resin as a precursor adopts the following technical scheme:

[0007] (1) According to the set proportion, water-soluble resin, aldehyde and alkaline catalyst, distilled water are added to a constant temperature water bath for stirring for 15-30 min to prepare a reaction solution, and the temperature of the constant temperature water bath is controlled at 50-85°C; 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).

[0008] (2) The pore-forming agent cyclodextrin is added to the above-mentioned stirring and clear reaction solution, the molar ratio of the cyclodextrin to the water-soluble resin is 1:(90-550), and the stirring is continued until all are dissolved, then the reaction is given to the oil phase material under high-speed stirring, the reaction is sheared into uniform micron-sized emulsion particles, and the temperature is raised for gelation to obtain a powder material suspension.

[0009] (3) The obtained suspension is centrifuged or suction filtered to obtain a powder material, the powder material is repeatedly washed with hot ethanol, then centrifuged or suction filtered to obtain a powder material, and the powder is dried at normal temperature and pressure, and then dried in a drying oven at 60-80°C.

[0010] (4) The dried powder material is added to a carbonization furnace, vacuumized at 130-180°C, then protected by inert gas, then heated to 400-600°C at a speed of 5-10°C / min, and kept for 20-60 min; then heated to 600-800°C at a speed of 5-10°C / min, and kept for 2-5 h; then heated to 800-1100°C at a speed of 5-10°C / min, and kept for 1-5 h, and naturally cooled to room temperature to obtain carbon aerogel powder;

[0011] (5) The carbon aerogel powder is added to a box-type atmosphere furnace, CO2 is introduced at a flow rate of 50-200 mL / min, and heated to 800-1000°C at a speed of 5-10°C / min, and kept 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 resin and water-soluble unsaturated polyester resin SR-1.

[0013] Preferably, in step (1), the aldehyde comprises one of formaldehyde, acetaldehyde, propyl aldehyde, 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 synergistically optimized, and finally activated carbon aerogel powder with a porous network structure, a pore size distribution of 0.5-18 nm, an average particle size of 3-17 µm, a specific surface area of 1100-2000 m 2 / g, and a tap density of 0.3 g / cm 3 -0.55 g / cm 3 is obtained.

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

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

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

[0019] Further, the raw material ratio and technical parameters of each step are synergistically optimized, and finally activated carbon aerogel powder with a porous network structure, a pore size distribution of 0.5-16 nm, an average particle size of 4-10 µm, a specific surface area of 1700-2000 m 2 / g, and a tap density of 0.3 g / cm 3 -0.42 g / cm 3 is obtained.

[0020] After the above technical scheme is adopted in the method for preparing carbon aerogel by using water-soluble resin as a precursor, the following positive effects are achieved:

[0021] (1) The present application first uses water-soluble resin as a precursor to prepare activated carbon aerogel powder with a porous network structure by using a microemulsion method, which has low production cost and is convenient for large-scale industrial production.

[0022] (2) The reaction raw material used in the application is mainly industrial-grade chemical raw material with rich source and low price. Compared with traditional biomass raw material, the ash content, pH value and heavy metal content are low, which can meet the requirements of super capacitor for high purity, low impurity and low ash content of activated carbon.

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

[0024] (4) The activated carbon aerogel powder with porous network structure prepared has an average particle size of 4-10 μm, a specific surface area of 1700-2000 m 2 / g, and a tap density of 0.3 g / cm 3 -0.42 g / cm 3 , which is particularly suitable for application in super capacitor electrode, lithium ion electrode, lithium sulfur electrode, etc., and can also be applied in catalyst carrier, heavy metal ion adsorption, gas adsorption and hydrogen storage material, and has important application value in energy storage, catalysis, adsorption and other nanometer material and technology related fields. DETAILED DESCRIPTION

[0025] The application will be further described below with specific examples, but not as a limitation to the application. Based on the technical scheme concept and examples in the application, any modification, equivalent replacement and improvement within the spirit and principles of the application should be included in the protection scope of the application.

[0026] Example 1

[0027] A method for preparing carbon aerogel with water-soluble resin as precursor, comprising the following steps:

[0028] (1) Take water-soluble phenolic resin, formaldehyde and sodium hydroxide, add them into distilled water and stir for 30 min, prepare a reaction solution with a density of 1.1 g / cm 3 , and place the reaction solution in a constant temperature water bath at 60°C and stir; the molar ratio of water-soluble phenolic resin to formaldehyde is 1:1; the molar ratio of water-soluble phenolic resin to sodium hydroxide is 1:500;

[0029] (2) adding a pore-forming agent cyclodextrin to the above stirred and clarified solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1:100, stirring until completely dissolved, then dropping the reactants into the high-speed stirred oil phase material, shearing into uniform micron-sized emulsion particles, and warming to gel to obtain a powder material suspension;

[0030] (3) separating the obtained suspension by centrifugation or suction filtration to obtain a powder material, repeatedly washing the powder material with hot ethanol, then separating by centrifugation or suction filtration to obtain a powder, drying the powder at room temperature and normal pressure, then drying at 80°C;

[0031] (4) adding the dried powder into a carbonization furnace, vacuumizing at 150°C, then protecting with inert gas, warming to 400°C at a rate of 5°C / min, maintaining for 60 min, continuing to warm to 800°C at a rate of 5°C / min, maintaining for 2 h, continuing to warm to 1000°C at a rate of 5°C / min, maintaining for 2 h, naturally cooling to room temperature, to obtain carbon aerogel powder;

[0032] (5) adding the carbon aerogel powder into a box-type atmosphere furnace, passing in CO2 at a flow rate of 100 mL / min, while warming to 1000°C at a rate of 10°C / min, maintaining for 10 h, to obtain activated carbon aerogel powder. The average particle size of the powder is 5-9 μm, the specific surface area is 1044 m 2 / g, and the tap density is 0.5 g / cm 3 .

[0033] Example 2

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

[0035] (1) adding water-soluble bisphenol A resin, formaldehyde and sodium bicarbonate into distilled water, stirring for 15 min, to prepare a reaction solution having a density of 1.2 g / cm 3 , and placing the reaction solution in a constant-temperature water bath at 70°C and stirring; the molar ratio of the water-soluble bisphenol A resin to formaldehyde is 1:1, and the molar ratio of the water-soluble bisphenol A resin to sodium bicarbonate is 1:500;

[0036] (2) adding a pore-forming agent cyclodextrin to the above stirred and clarified solution, wherein the mass ratio of cyclodextrin to water-soluble resin is 1:200, stirring until completely dissolved, then dropping the reactants into the high-speed stirred oil phase material, shearing into uniform micron-sized emulsion particles, and warming to gel to obtain a powder material suspension;

[0037] (3) separating the obtained suspension by centrifugation or suction filtration to obtain a powder material, repeatedly washing the powder material with hot ethanol, then separating by centrifugation or suction filtration to obtain a powder, drying the powder at room temperature and normal pressure, then drying 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 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 by using water-soluble resin as precursor, comprising the following steps:

[0056] (1) water-soluble phenolic resin, furfural and potassium hydroxide are added into distilled water and stirred for 20 min to prepare a reaction solution with a density of 1.2 g / cm 3 , and the reaction solution is stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble phenolic resin to the furfural is 1:2, and the molar ratio of the water-soluble phenolic resin to the potassium hydroxide is 1:500;

[0057] (2) a pore-forming agent starch is added into the above stirred and clarified solution, the mass ratio of the starch to the water-soluble resin is 1:500, after stirring until completely dissolved, the reaction is dropped into an oil phase material under high-speed stirring, sheared into uniform micron-sized emulsion particles, and heated to gel to obtain a powder material suspension;

[0058] (3) the obtained suspension is centrifuged or suction-filtered to obtain a powder material, the powder material is repeatedly washed with hot ethanol, then centrifuged or suction-filtered to obtain a powder, the powder is dried at normal temperature and pressure, and then heated to 70°C for drying;

[0059] (4) the dried powder is added into a carbonization furnace, vacuumized at 150°C, then protected by inert gas, heated to 500°C at a speed of 5°C / min, kept for 60 min, continuously heated to 800°C at a speed of 5°C / min, kept for 2 h, continuously heated to 950°C at a speed of 5°C / min, kept for 2 h, naturally cooled to room temperature, and a carbon aerogel powder is obtained;

[0060] (5) the carbon aerogel powder is added into a box-type atmosphere furnace, CO2 is introduced at a flow rate of 150 mL / min, and heated to 850°C at a speed of 10°C / min, kept for 12 h, and an activated carbon aerogel powder is obtained. The average particle size of the powder is 5-9 μm, the specific surface area is 1632 m 2 / g, and the tap density is 0.4 g / cm 3 .

[0061] Example 6

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

[0063] (1) water-soluble bisphenol A resin, propyl aldehyde and sodium hydroxide are added into distilled water and stirred for 20 min to prepare a reaction solution with a density of 0.9 g / cm 3 , and the reaction solution is stirred in a constant temperature water bath at 70°C; the molar ratio of the water-soluble bisphenol A resin to the propyl aldehyde is 1:1, and the molar ratio of the water-soluble bisphenol A resin to the sodium hydroxide is 1:500;

[0064] (2) In the above stirring and clarifying solution, a pore-forming agent starch is added, wherein the mass ratio of starch to water-soluble resin is 1:500, and after stirring until completely dissolved, the reactants are dropped into the high-speed stirring oil phase material, sheared into uniform micron-sized emulsion particles, and heated to gel to obtain a powder material suspension.

[0065] (3) The obtained suspension is separated by centrifugation or suction filtration to obtain a powder material, which is repeatedly washed with hot ethanol and then separated by centrifugation or suction filtration to obtain a powder. After drying at room temperature and normal pressure, the powder is dried at 80°C;

[0066] (4) The dried powder is added to a carbonization furnace, vacuumed at 150°C, and then protected by inert gas. The temperature is increased to 500°C at a rate of 5°C / min, and the temperature is maintained for 60 min. The temperature is continuously increased to 800°C at a rate of 5°C / min, and the temperature is maintained for 1 h. The temperature is continuously increased to 1000°C at a rate of 5°C / min, and the temperature is maintained for 3 h. The temperature is naturally decreased to room temperature to obtain carbon aerogel powder;

[0067] (5) The carbon aerogel powder is added to a box-type atmosphere furnace, and CO2 is introduced at a flow rate of 100 mL / min while the temperature is increased to 900°C at a rate of 10°C / min. The temperature is maintained for 12 h to obtain activated carbon aerogel powder. The average particle size of the powder is 5-9 μm, the specific surface area is 1662 m 2 / g, and the tap density is 0.3 g / cm 3 .

[0068] Example 7

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

[0070] (1) A water-soluble unsaturated polyester resin (SR-1), acetaldehyde, and sodium bicarbonate are added to distilled water and stirred for 20 min to prepare a reaction solution with a density of 1.0 g / cm 3 , and the reaction solution is placed in a constant-temperature water bath at 70°C and stirred. The molar ratio of the water-soluble unsaturated polyester resin (SR-1) to acetaldehyde is 1:3, and the molar ratio of the water-soluble unsaturated polyester resin (SR-1) to sodium bicarbonate is 1:300;

[0071] (2) In the above stirring and clarifying solution, a pore-forming agent starch is added, wherein the mass ratio of starch to water-soluble resin is 1:500, and after stirring until completely dissolved, the reactants are dropped into the high-speed stirring oil phase material, sheared into uniform micron-sized emulsion particles, and heated to gel to obtain a powder material suspension.

[0072] (3) The obtained suspension is separated by centrifugation or suction filtration to obtain a powder, the powder is repeatedly washed with hot ethanol, and then separated by centrifugation or suction filtration to obtain a powder, and the powder is dried at room temperature and normal pressure and then dried at 70°C;

[0073] (4) The dried powder is added into a carbonization furnace, vacuumized at 150°C, and then protected by inert gas, heated to 500°C at a speed of 5°C / min, kept for 60 min, continuously heated to 800°C at a speed of 5°C / min, kept for 1 h, continuously heated to 900°C at a speed of 5°C / min, kept for 2 h, and naturally cooled to room temperature to obtain a carbon aerogel powder;

[0074] (5) The carbon aerogel powder is added into a box-type atmosphere furnace, CO2 is passed in at a flow rate of 150 mL / min, and meanwhile, heated to 950°C at a speed of 10°C / min, kept for 11 h to obtain an activated carbon aerogel powder. The average particle size of the powder is 5-9 μm, the specific surface area is 1603 m 2 / g, and the tap density is 0.5 g / cm 3 .

[0075] Example 8

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

[0077] (1) A water-soluble phenolic resin, acetaldehyde and hexamethylenetetramine are added into distilled water and stirred for 15 min to prepare a reaction solution with a density of 1.1 g / cm 3 , and the reaction solution is placed in a constant-temperature water bath at 70°C and stirred; the molar ratio of the water-soluble phenolic resin to acetaldehyde is 1:1, and the molar ratio of the water-soluble phenolic resin to hexamethylenetetramine is 1:300;

[0078] (2) A pore-forming agent cyclodextrin is added into the above-mentioned stirred and clarified solution, the mass ratio of the cyclodextrin to the water-soluble resin is 1:200, after stirring until completely dissolved, the reaction is dropped into an oil-phase substance stirred at high speed, sheared into uniform micron-sized emulsion particles, and heated to gel to obtain a powder suspension.

[0079] (3) The obtained suspension is separated by centrifugation or suction filtration to obtain a powder, the powder is repeatedly washed with hot ethanol, and then separated by centrifugation or suction filtration to obtain a powder, and the powder is dried at room temperature and normal pressure and then dried at 70°C;

[0080] (4) the dried powder is added into a carbonization furnace, vacuum is extracted at 150℃, and then inert gas is filled for protection, the temperature is raised to 500℃ at a speed of 5℃ / min, and then the temperature is kept for 60min, the temperature is continuously raised to 800℃ at a speed of 5℃ / min, and then the temperature is kept for 1h, the temperature is continuously raised to 1050℃ at a speed of 5℃ / min, and then the temperature is kept for 1h, and then the temperature is naturally reduced to room temperature, and carbon aerogel powder is obtained;

[0081] (5) the carbon aerogel powder is added into a box-type atmosphere furnace, CO2 is filled in at a flow rate of 100mL / min, and the temperature is raised to 900℃ at a speed of 10℃ / min, and then the temperature is kept for 10h, and then activated carbon aerogel powder is obtained. The average particle size of the powder is 5-9μm, the specific surface area is 1685m 2 / g, and the tap density is 0.3 g / cm 3 .

[0082] The carbon aerogel powder is prepared by using water-soluble resin as a precursor, mainly by combining sol-gel and microemulsion technology, and the raw materials of the present application are mainly industrial-grade chemical raw materials which are abundant in source and low in price. Compared with traditional biomass raw materials, the carbon aerogel powder has lower ash content, pH value and heavy metal content, and can meet the requirements of supercapacitors for high-purity, low-impurity and low-ash activated carbon. Compared with traditional resorcinol and phloroglucinol, the carbon aerogel powder is low in price and suitable for large-scale industrial production. According to different application directions, the present application can configure reaction solutions with different reaction concentrations, select appropriate catalysts, select appropriate types and amounts of surfactants, disperse the reaction solution into oil phase materials with a density equivalent to that of water solution at different stirring speeds, form microemulsion particles, control appropriate temperature and time to form micron-level organic aerogel powder, and obtain carbon aerogel powder with different theoretical densities and different specific surface areas through separation, carbonization and activation. The prepared carbon aerogel powder also has the characteristics of high tap density, large specific surface area, high conductivity and good supercapacitor electrode coating effect. The carbon aerogel powder is particularly suitable for application in supercapacitor electrodes, lithium ion electrodes, lithium-sulfur electrodes and the like, and can also be applied in catalyst carriers, heavy metal ion adsorption, gas adsorption and hydrogen storage materials, and has important application value in the fields of energy storage, catalysis, adsorption and other nanomaterials and technologies.

[0083] Although the embodiments of the present application have been disclosed as above, they are not limited to the uses listed in the specification and embodiments, and can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details and the figures shown and described herein. In order to describe the present application, a method for continuously preparing carbon aerogel precursor of the present application is further described in detail below in combination with examples. However, the present application is not limited to the examples.

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 water-soluble resin to aldehyde is 1:1-3. The molar ratio of water-soluble resin to alkaline catalyst is 1:(250-650). (2) Add pore-forming agent cyclodextrin to the above stirred and clarified reaction solution, wherein the molar ratio of cyclodextrin to water-soluble resin is 1: (90-550), continue stirring until completely dissolved, 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 water-soluble resin includes one of phenolic resin, bisphenol A type resin, and water-soluble unsaturated polyester resin SR-1.

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 aldehydes include one of formaldehyde, acetaldehyde, propionaldehyde, and furfural.

4. 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.

5. A method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 1, 2, 3, or 4, characterized in that: By synergistically optimizing and controlling the raw material ratios and technical parameters at each step, a particle size distribution of 0.5–18 nm, an average particle size of 3–17 μm, and a specific surface area of ​​1100–2000 m² was obtained. 2 / g, tap density 0.3 g / cm³ 3 ~0.55 g / cm 3 Activated carbon aerogel powder with a porous network structure.

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 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.

7. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 6, characterized in that: In step (1), the density of the prepared reaction solution is 0.8-1.2 g / cm³. 3 .

8. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 7, 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 molar ratio of the cyclodextrin to the water-soluble resin is 1:(100~500).

9. The method for preparing carbon aerogel using a water-soluble resin as a precursor as described in claim 8, characterized in that: 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 obtained. 2 / g, tap density 0.3 g / cm³ 3 ~0.42 g / cm 3 Activated carbon aerogel powder with a porous network structure.