A rapid method for the preparation of porous carbon aerogels for supercapacitors
The preparation of porous carbon aerogels by spray phase inversion method solves the problems of complex and high cost in the preparation process of porous carbon materials, realizes efficient, rapid and continuous production, and improves the electrochemical performance and stability of the materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LANZHOU UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2024-01-03
- Publication Date
- 2026-07-10
AI Technical Summary
Existing porous carbon material preparation processes are complex and costly. Existing pore-forming methods lead to complex and costly porous carbon preparation processes, and also reduce the carbon yield of porous carbon.
Porous carbon aerogels were prepared by spray phase inversion, including steps such as preparation of polyacrylonitrile solution, atomization phase inversion, filtration and washing, freeze drying, thermal crosslinking and carbonization. The structure of the porous carbon aerogels was controlled by adjusting the spray phase inversion conditions and solvent composition.
Rapid preparation of porous carbon aerogels was achieved, which possess a continuous carbon aerogel framework and a porous interconnected channel structure, thereby improving the electronic conductivity network and ion transport pathway, and enhancing the rate performance and cycle stability of the material.
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Figure CN117819522B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of supercapacitor electrode material preparation technology, and in particular to a rapid preparation method for porous carbon aerogel for supercapacitors. Background Technology
[0002] Supercapacitors, as fast-charge and discharge energy storage devices, are characterized by high power density, long service life, and high safety. Porous carbon materials, as commonly used electrode materials for supercapacitors, are characterized by stable electrochemical properties, fast charge and discharge speeds, and simple preparation.
[0003] However, in the preparation of porous carbon materials, microporous structures are often generated by chemical activation etching or sacrificial template methods. These pore-forming methods make the preparation process of porous carbon more complicated, increase costs, and also greatly reduce the carbon yield of porous carbon. Summary of the Invention
[0004] 1. Technical problems to be solved
[0005] The purpose of this invention is to solve the problem that the existing pore-forming methods make the preparation process of porous carbon more complicated and costly, and to propose a rapid preparation method for porous carbon aerogels for supercapacitors.
[0006] 2. Technical Solution
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A rapid preparation method for porous carbon aerogels for supercapacitors includes the following steps:
[0009] Step 1: Preparation of polyacrylonitrile solution: Take polyacrylonitrile powder and solvent according to the mass ratio of (0.5-20):(50-150), stir and dissolve the polyacrylonitrile powder in the solvent at a certain temperature to obtain polyacrylonitrile solution;
[0010] Step 2: Atomization phase inversion: The polyacrylonitrile solution prepared in step 1 is added to the high-pressure atomizing pneumatic spray gun and atomized into the coagulation bath. The polyacrylonitrile solution is phase-transformed into polyacrylonitrile aerogel particles in the coagulation bath.
[0011] Step 3: Filtration and washing: Use deionized water to filter and wash the polyacrylonitrile aerogel particles prepared in step 2 3-5 times to obtain pure polyacrylonitrile aerogel particles.
[0012] Step 4: Drying: Freeze the polyacrylonitrile aerogel particles prepared in step 3, and then freeze-dry them to obtain polyacrylonitrile aerogel.
[0013] Step 5: Thermal crosslinking: The polyacrylonitrile aerogel prepared in step 4 is placed in a muffle furnace for heating and thermal crosslinking to obtain pre-oxidized polyacrylonitrile aerogel.
[0014] Step 6: Carbonization: The pre-oxidized polyacrylonitrile aerogel prepared in step 5 is placed in a tube furnace and subjected to high-temperature carbonization in an inert gas to obtain porous carbon aerogel.
[0015] Preferably, the molecular weight of the polyacrylonitrile in step 1 is in the range of 20,000-100,000; the solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, ethylene carbonate, methanol, ethanol, ethylene glycol, glycerol, acetone, butanone, ethyl acetoacetate, and ethyl acetate.
[0016] Preferably, in step 1, the polyacrylonitrile solution is dissolved at a temperature of 25-70°C and the stirring speed is 100-2000 r / min.
[0017] Preferably, the coagulation bath in step 2 is composed of one or more of water, ethanol, glycerol, acetone, and butanone.
[0018] Preferably, the atomizing spraying pressure in step 2 is 0.1-0.4 MPa.
[0019] Preferably, the pre-oxidation temperature in step 5 is 220-280℃, and the pre-oxidation time is 2-8h.
[0020] Preferably, in step 6, the carbonization temperature is 800-1300℃ and the carbonization time is 5-10h.
[0021] 3. Beneficial effects
[0022] Compared with the prior art, the advantages of this invention are:
[0023] (1) The spray phase inversion method used in this invention is simple to operate and can produce porous carbon aerogels in a high-efficiency, fast and continuous manner. The structure of the final porous carbon aerogel can be controlled by adjusting the solvent composition of the polymer solution, the solvent composition of the coagulation bath, or the spray phase inversion conditions (temperature, pressure), so as to affect its electrochemical performance.
[0024] (2) In this invention, the porous carbon aerogel has a continuous carbon aerogel skeleton and a porous interconnected channel structure, which gives it an excellent electronic conductivity network and a fast ion transport pathway, thus improving the rate performance and cycle stability of the material. Attached Figure Description
[0025] Figure 1This is a schematic diagram of the three-dimensional structure of the polyacrylonitrile aerogel and porous carbon aerogel prepared by spray phase inversion proposed in this invention.
[0026] Figure 2 These are scanning electron microscope images of the porous carbon aerogels of Examples 2-4 of the present invention.
[0027] Figure 3 The nitrogen isotherm adsorption-desorption curves are shown for the porous carbon aerogels of Examples 2-4 of this invention.
[0028] Figure 4 The porous carbon aerogels of Examples 1 to 3 of this invention are in 0.5A g -1 The measured charge-discharge curves.
[0029] Figure 5 The porous carbon aerogels of Examples 1 to 3 of this invention are in the range of 0.5-50 A g. -1 Charging and discharging rate performance measured at current density. Detailed Implementation
[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0031] Example 1:
[0032] Reference Figure 1 A rapid preparation method for porous carbon aerogels for supercapacitors includes the following steps:
[0033] Step 1: Preparation of polyacrylonitrile solution: Take polyacrylonitrile powder and solvent at a mass ratio of (0.5-20):(50-150), and stir the polyacrylonitrile powder in the solvent at a certain temperature to obtain a polyacrylonitrile solution. The molecular weight range of polyacrylonitrile is 20,000-100,000. The solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, ethylene carbonate, methanol, ethanol, ethylene glycol, glycerol, acetone, butanone, ethyl acetoacetate, and ethyl acetate.
[0034] Step 2: Atomization phase inversion: The polyacrylonitrile solution prepared in Step 1 is added to a high-pressure atomizing pneumatic spray gun and atomized into a coagulation bath. The polyacrylonitrile solution is phase-converted into polyacrylonitrile aerogel particles in the coagulation bath. The coagulation bath is composed of one or more of water, ethanol, glycerol, acetone, and butanone.
[0035] Step 3: Filtration and washing: Use deionized water to filter and wash the polyacrylonitrile aerogel particles prepared in step 2 3-5 times to obtain pure polyacrylonitrile aerogel particles.
[0036] Step 4: Drying: Freeze the polyacrylonitrile aerogel particles prepared in step 3, and then freeze-dry them to obtain polyacrylonitrile aerogel.
[0037] Step 5: Thermal crosslinking: The polyacrylonitrile aerogel prepared in step 4 is placed in a muffle furnace for heating and thermal crosslinking to obtain pre-oxidized polyacrylonitrile aerogel.
[0038] Step 6: Carbonization: The pre-oxidized polyacrylonitrile aerogel prepared in step 5 is placed in a tube furnace and subjected to high-temperature carbonization in an inert gas to obtain porous carbon aerogel.
[0039] In this embodiment, the spray phase inversion method is simple to operate and can produce porous carbon aerogels efficiently, quickly and continuously. The structure of the final porous carbon aerogel can be controlled by adjusting the solvent composition of the polymer solution, the solvent composition of the coagulation bath, or the spray phase inversion conditions (temperature, pressure), thereby affecting its electrochemical performance.
[0040] In this embodiment, the prepared porous carbon aerogel, due to its continuous carbon aerogel framework and porous interconnected channel structure, has an excellent electronic conductivity network and a fast ion transport pathway, which improves the rate performance and cycle stability of the material.
[0041] Example 2:
[0042] It has the implementation content of the above embodiments, wherein the specific implementation methods of the above embodiments can be referred to the above description, and the embodiments here will not be described in detail again; however, the difference between the embodiments in this application and the above embodiments is that:
[0043] In this embodiment, a rapid preparation method for porous carbon aerogel for supercapacitors includes the following steps:
[0044] 1) Dissolve 1g of polyacrylonitrile powder in 90mL of dimethyl sulfoxide solvent and stir magnetically for 6h to fully dissolve and obtain a polyacrylonitrile solution.
[0045] 2) Pour the polyacrylonitrile solution into a high-pressure spray gun and spray it onto the water being stirred under a pressure of 0.3 MPa, keeping the water temperature between 20-30℃, to obtain a polyacrylonitrile aerogel dispersion.
[0046] 3) The polyacrylonitrile aerogel dispersion was filtered and washed, rinsed three times with deionized water, and then freeze-dried to prepare polyacrylonitrile aerogel.
[0047] 4) The polyacrylonitrile aerogel was placed in a muffle furnace and pre-oxidized in air atmosphere. The pre-oxidation program was a step-by-step heating process, pre-oxidizing at 220℃, 250℃ and 280℃ for 2, 2 and 3 hours respectively, to obtain pre-oxidized polyacrylonitrile aerogel.
[0048] 5) The pre-oxidized polyacrylonitrile aerogel was placed in a tube furnace for pyrolysis. The pyrolysis program was 5℃ min. -1 The temperature was raised to 800℃ and held for 3 hours to obtain porous carbon aerogel sample A.
[0049] 6) Sample A was used as the negative electrode active material in a supercapacitor to assemble a three-electrode test system. A constant current charge-discharge test was performed on the sample using an electrochemical workstation. The charge-discharge test parameters were as follows: current density of 0.5, 1, 2, 3, 4, 5, 20, and 50 Ag. -1 The voltage is between -1 and 0V.
[0050] In the porous carbon aerogel preparation method provided in this example, the specific surface area of the prepared porous carbon aerogel sample A is 210.3 m². 2 g -1 At 0.5A g -1 The specific capacity is 206.5 F g. -1 .
[0051] In this embodiment, refer to Figure 2 It can be seen that all three samples exhibit a continuous carbon framework network with a three-dimensional interpenetrating structure, and also have a rich network of interconnected mesoporous channels. (Refer to...) Figure 3 It can be seen that all three samples have abundant microporous and mesoporous structures.
[0052] In this embodiment, from Figure 4 It can be seen that sample A has the best charge-discharge capacity. Furthermore, the charge-discharge curves of all three samples exhibit a symmetrical triangular curve, consistent with the characteristics of double-layer energy storage. Figure 5 As can be seen from the example, sample A in Example 1 has the best energy storage performance under different current densities.
[0053] Example 3:
[0054] It has the implementation content of the above embodiments, wherein the specific implementation methods of the above embodiments can be referred to the above description, and the embodiments here will not be described in detail again; however, the difference between the embodiments in this application and the above embodiments is that:
[0055] In this embodiment, a rapid preparation method for porous carbon aerogel for supercapacitors includes the following steps:
[0056] 1) Dissolve 1g of polyacrylonitrile powder in a mixed solvent of 48mL N,N-dimethylformamide and 53mL dimethyl sulfoxide, and stir magnetically for 6h to fully dissolve and obtain a polyacrylonitrile solution.
[0057] 2) Pour the polyacrylonitrile solution into a high-pressure spray gun and spray it onto the water being stirred under a pressure of 0.3 MPa, keeping the water temperature between 20-30℃, to obtain a polyacrylonitrile aerogel dispersion.
[0058] 3) The polyacrylonitrile aerogel dispersion was filtered and washed, rinsed three times with deionized water, and then freeze-dried to prepare polyacrylonitrile aerogel.
[0059] 4) The polyacrylonitrile aerogel was placed in a muffle furnace and pre-oxidized in air atmosphere. The pre-oxidation program was a step-by-step heating process, pre-oxidizing at 220℃, 250℃ and 280℃ for 2, 2 and 3 hours respectively, to obtain pre-oxidized polyacrylonitrile aerogel.
[0060] 5) The pre-oxidized polyacrylonitrile aerogel was placed in a tube furnace for pyrolysis. The pyrolysis program was 5℃ min. -1 The temperature was raised to 800℃ and held for 3 hours to obtain porous carbon aerogel sample B.
[0061] 6) Sample A was used as the negative electrode active material in a supercapacitor to assemble a three-electrode test system. A constant current charge-discharge test was performed on the sample using an electrochemical workstation. The charge-discharge test parameters were as follows: current density of 0.5, 1, 2, 3, 4, 5, 20, and 50 Ag. -1 The voltage is between -1 and 0V.
[0062] In the porous carbon aerogel preparation method provided in this example, the specific surface area of the prepared porous carbon aerogel sample B is 182 m². 2 g -1 At 0.5A g -1 The specific capacity is 180 F g. -1 .
[0063] Example 4:
[0064] It has the implementation content of the above embodiments, wherein the specific implementation methods of the above embodiments can be referred to the above description, and the embodiments here will not be described in detail again; however, the difference between the embodiments in this application and the above embodiments is that:
[0065] In this embodiment, a rapid preparation method for porous carbon aerogel for supercapacitors includes the following steps:
[0066] 1) Dissolve 1g of polyacrylonitrile powder in 104mL of N,N-dimethylformamide solvent and stir magnetically for 6h to fully dissolve and obtain a polyacrylonitrile solution.
[0067] 2) Pour the polyacrylonitrile solution into a high-pressure spray gun and spray it onto the water being stirred under a pressure of 0.3 MPa, keeping the water temperature between 20-30℃, to obtain a polyacrylonitrile aerogel dispersion.
[0068] 3) The polyacrylonitrile aerogel dispersion was filtered and washed, rinsed three times with deionized water, and then freeze-dried to prepare polyacrylonitrile aerogel.
[0069] 4) The polyacrylonitrile aerogel was placed in a muffle furnace and pre-oxidized in air atmosphere. The pre-oxidation program was a step-by-step heating process, pre-oxidizing at 220℃, 250℃ and 280℃ for 2, 2 and 3 hours respectively, to obtain pre-oxidized polyacrylonitrile aerogel.
[0070] 5) The pre-oxidized polyacrylonitrile aerogel was placed in a tube furnace for pyrolysis. The pyrolysis program was 5℃ min. -1 The temperature was raised to 800℃ and held for 3 hours to obtain porous carbon aerogel sample C.
[0071] 6) Sample A was used as the negative electrode active material in a supercapacitor to assemble a three-electrode test system. A constant current charge-discharge test was performed on the sample using an electrochemical workstation. The charge-discharge test parameters were as follows: current density of 0.5, 1, 2, 3, 4, 5, 20, and 50 Ag. -1 The voltage is between -1 and 0V.
[0072] In the porous carbon aerogel preparation method provided in this example, the specific surface area of the prepared porous carbon aerogel sample is 85.7 m² / C. 2 g -1 At 0.5A g -1 The specific capacity is 155.5 F g. -1 .
[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A rapid preparation method for porous carbon aerogels for supercapacitors, characterized in that, Includes the following steps: Step 1: Preparation of polyacrylonitrile solution: Take polyacrylonitrile powder and solvent in a mass ratio of (0.5-20):(50-150), and stir the polyacrylonitrile powder in the solvent at a certain temperature to obtain polyacrylonitrile solution; Step 2: Atomization phase inversion: The polyacrylonitrile solution prepared in step 1 is added to the high-pressure atomizing pneumatic spray gun and atomized into the coagulation bath. The polyacrylonitrile solution is phase-transformed into polyacrylonitrile aerogel particles in the coagulation bath. Step 3: Filtration and washing: Use deionized water to filter and wash the polyacrylonitrile aerogel particles prepared in step 2 3-5 times to obtain pure polyacrylonitrile aerogel particles. Step 4: Drying: Freeze the polyacrylonitrile aerogel particles prepared in step 3, and then freeze-dry them to obtain polyacrylonitrile aerogel. Step 5: Thermal crosslinking: The polyacrylonitrile aerogel prepared in step 4 is placed in a muffle furnace for heating and thermal crosslinking to obtain pre-oxidized polyacrylonitrile aerogel. Step 6: Carbonization: The pre-oxidized polyacrylonitrile aerogel prepared in step 5 is placed in a tube furnace and subjected to high-temperature carbonization in an inert gas to obtain porous carbon aerogel.
2. The rapid preparation method of porous carbon aerogel for supercapacitors according to claim 1, characterized in that, In step 1, the molecular weight of the polyacrylonitrile ranges from 20,000 to 100,000; the solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and ethylene carbonate.
3. The rapid preparation method of porous carbon aerogel for supercapacitors according to claim 1, characterized in that, In step 1, the polyacrylonitrile solution is dissolved at a temperature of 25-70 ℃, and the stirring speed is 100-2000 r / min.
4. The rapid preparation method of porous carbon aerogel for supercapacitors according to claim 1, characterized in that, The coagulation bath in step 2 is composed of one or more of water, ethanol, glycerol, acetone, and butanone.
5. The rapid preparation method of porous carbon aerogel for supercapacitors according to claim 1, characterized in that, In step 2, the atomization spraying pressure is 0.1-0.4 MPa.
6. The rapid preparation method of porous carbon aerogel for supercapacitors according to claim 1, characterized in that, In step 5, the pre-oxidation temperature is 220-280 ℃, and the pre-oxidation time is 2-8 h.
7. The rapid preparation method of porous carbon aerogel for supercapacitors according to claim 1, characterized in that, In step 6, the carbonization temperature is 800-1300 ℃ and the carbonization time is 5-10 h.