A method for recycling and regenerating supercapacitor activated carbon material and its application

Abstract

The invention relates to the technical field of supercapacitor recycling and discloses a method for recycling and regenerating activated carbon materials for supercapacitors. The method comprises the following steps: S1: cutting electrode pole pieces into small pieces of 1-10 mm; S2: immersing the electrode pole pieces obtained in S1 in a mixed solvent, and separating aluminum foil and crude activated carbon under high temperature, high pressure and ultrasonic conditions; S3: adding the crude activated carbon obtained in S2 to a No. 1 organic solvent, and obtaining activated carbon with extremely low impurity content under negative pressure and ultrasonic conditions; S4: performing thermal activation treatment on the activated carbon with extremely low impurity content obtained in S3 to obtain high-quality regenerated activated carbon; and an application of the activated carbon material for supercapacitors. The high-quality regenerated activated carbon obtained by the method is used in supercapacitors. The technical solution of the invention can obtain high-quality activated carbon, which is directly used in supercapacitors, thereby realizing the recycling of the activated carbon.

Description

Technical Field

[0001] The present invention relates to the technical field of supercapacitor recycling, and in particular to a method for recycling and regenerating supercapacitor activated carbon materials and applications thereof. Background Art

[0002] With the development of society and the advancement of science and technology, people have increasingly higher requirements for the charging and discharging speed, lifespan, power density, and energy density of energy storage components. Therefore, supercapacitors with fast charging and discharging speeds, long lifespan, high power density, and good safety performance have gained popularity. They are widely used in digital, automotive, medical, health, power electronics, communications, energy, military and other fields. As the application fields of supercapacitors expand, their usage is increasing year by year. Therefore, the number of retired supercapacitors is also increasing year by year. Directly discarding them not only results in a large waste of resources, but also causes environmental pollution.

[0003] At present, commercial supercapacitors on the market are mainly electric double-layer capacitors (EDLCs). As the positive and negative electrode materials of supercapacitors, activated carbon plays a key role. However, due to the high manufacturing cost of activated carbon for supercapacitors, the price of activated carbon for supercapacitors has remained high, which makes the manufacturing cost of supercapacitors relatively high, which seriously limits the application and promotion of supercapacitors. Therefore, effective recycling and reuse of activated carbon for supercapacitors can not only recycle activated carbon, but also reduce the manufacturing cost of supercapacitors. At the same time, it can alleviate the pressure of resource shortage, prevent environmental pollution, and promote the healthy development of the supercapacitor industry.

[0004] Existing methods for recycling activated carbon materials for supercapacitors generally employ a method for recycling waste supercapacitors with patent number CN105618459A, comprising the following steps: 1) piling the waste supercapacitors together for discharge treatment; 2) crushing the waste supercapacitors into flakes with a diameter of 1-5 mm in a sealed explosion-proof crusher, spraying a spray liquid while crushing, and dissolving the quaternary ammonium salt electrolyte in the waste supercapacitors in the spray liquid; 3) separating the supercapacitor shell by stirring and separating; 4) centrifuging the suspension after stirring and separating in step 3) to obtain a mixture of flakes, the electrolyte, and the spray liquid; 5) placing the flakes in a constant temperature roasting furnace and roasting them to carbonize the diaphragm and the binder; and 6) recovering the activated carbon and aluminum foil separately by centrifugal separation. Activated carbon can be recycled through this technical solution. However, this technical solution involves carbonizing a large amount of diaphragms together with electrodes. Carbonization of the diaphragms results in activated carbon with a low specific surface area. Furthermore, carbonization together with aluminum foil will lead to the doping of metallic aluminum in the activated carbon. Therefore, this technical solution results in a crude activated carbon product with mixed components, which cannot be directly used in supercapacitors. Summary of the Invention

[0005] The present invention aims to provide a method for recycling and regenerating supercapacitor activated carbon materials to obtain high-quality activated carbon for direct use in supercapacitors.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for recovering and regenerating supercapacitor activated carbon material, comprising the following steps:

[0007] S1: Disassemble the retired supercapacitor, remove the electrode plates, and cut the electrode plates into small pieces of 1-10mm;

[0008] S2: Immerse the electrode sheet obtained in S1 in a mixed solvent, wherein the mass ratio of the electrode sheet to the mixed solvent is 1:20-1:5, react the resulting mixture under high temperature and high pressure conditions for 2-12 hours, then ultrasonically treat for 10-60 minutes at an ultrasonic power of 100-600W, and finally centrifuge and dry to separate the aluminum foil and crude activated carbon. Repeat the above operation 1-3 times;

[0009] S3: adding the crude activated carbon obtained in S2 to an organic solvent No. 1, wherein the mass ratio of the crude activated carbon to the organic solvent No. 1 is 1:20-1:3, heating the mixture of the crude activated carbon and the organic solvent No. 1 to 20-60° C. under negative pressure, soaking for 4-24 hours, and then ultrasonically treating for 20-60 minutes at an ultrasonic power of 300-600W. Finally, centrifuging and drying are performed to obtain activated carbon with an extremely low impurity content, and repeating the above operation 1-3 times;

[0010] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon.

[0011] The beneficial effects of this solution are as follows: This technical solution is to place the electrode plates in a mixed solvent under high temperature and high pressure conditions, remove the binder and electrolyte on the electrode plates, and apply energy to the surface of the electrode plates under the action of ultrasound, so that the binder and electrolyte adsorbed on the surface of the electrode plates are quickly dissolved in the mixed solvent, without heating the mixed solvent to a very high temperature, so that the binder and electrolyte on the electrode plates can be removed, and then through centrifugation and drying, the aluminum foil and the crude activated carbon can be separated, and then under negative pressure conditions, the crude activated carbon is immersed in an organic solvent No. 1, and under the action of negative pressure and ultrasound, the organic solvent No. 1 enters the micropores of the crude activated carbon and removes the residual electrolyte in the micropores, and then through centrifugation and drying, activated carbon with extremely low impurity content is obtained, and by thermal activation treatment of the activated carbon with extremely low impurity content, the excess oxygen-containing functional groups, surface defects, and a small amount of blocked pore materials adsorbed on the activated carbon are decomposed or vaporized, the structure of the activated carbon is restored, and high-quality regenerated activated carbon is obtained.

[0012] Due to the use of ultrasonic technology, this technical solution can provide energy for the electrode plates and activated carbon crude products, accelerate the dissolution of substances adsorbed on the surfaces of the electrode plates and activated carbon crude products, and has the advantages of saving energy and mixed solvents. At the same time, it can prevent the temperature of the mixed solvent and the No. 1 organic solvent from being too high, which may cause the collapse of the activated carbon.

[0013] This technical solution has the advantages of low recycling cost, green environmental protection, and the ability to achieve resource recycling. The activated carbon recovered and regenerated through this technical solution has its physical and chemical properties, specific surface area, electrical conductivity and other indicators restored, and the obtained activated carbon is high-quality, which can be directly used in supercapacitors, realizing the recycling and reuse of activated carbon, reducing the manufacturing cost of supercapacitors, and at the same time, reducing environmental pollution and promoting the healthy development of the supercapacitor industry.

[0014] Furthermore, the mixed solvent in S2 is water or a combination of water and a second organic solvent, and the mass ratio of water to the second organic solvent is 1:0-100:1, wherein the second organic solvent is any one of ethanol, acetone and isopropanol.

[0015] The beneficial effect of this solution is that the binder and electrolyte adsorbed on the electrode plates are easily dissolved in the mixed solvent, thereby facilitating the separation of the aluminum foil and the crude activated carbon without causing damage to the activated carbon structure. At the same time, the mixed solvent can be recycled and reused, reducing processing costs.

[0016] Furthermore, the temperature in S2 is 60-200° C., and the pressure is 0.3-2 MPa.

[0017] The beneficial effect of this solution is that under the conditions of a temperature of 60-200° C. and a pressure of 0.3-2 MPa, the binder and electrolyte in the electrode plate obtained in S1 can be dissolved more quickly and completely, thereby improving the processing efficiency.

[0018] Furthermore, the organic solvent No. 1 in S3 is any one of ethylene carbonate, propylene carbonate, acetonitrile, ethyl ether and methyl ethyl ether, or a mixture of several of them.

[0019] The beneficial effects of this solution are: since ethylene carbonate, propylene carbonate, acetonitrile, ethyl ether and methyl ethyl ether are solvents for supercapacitor electrolytes, the use of No. 1 organic solvent can remove the electrolyte adsorbed on the activated carbon, and at the same time, can ensure that the activated carbon structure is not destroyed during the recovery process.

[0020] Furthermore, the negative pressure in S3 is 100-1000Pa.

[0021] The beneficial effects of this scheme are as follows: under a negative pressure of 100-1000Pa, the crude activated carbon obtained in S2 is immersed in an organic solvent No. 1, which enables the organic solvent No. 1 to enter the micropores of the activated carbon more easily and quickly, remove the electrolyte in the micropores, and obtain activated carbon with extremely low impurity content; while under normal pressure conditions, the organic solvent No. 1 cannot enter the extremely small micropores of the activated carbon, resulting in incomplete removal of the electrolyte, which affects the application of the activated carbon.

[0022] Furthermore, the drying temperature in S2 and S3 is both 80-120° C., and the drying time is both 6-24 h.

[0023] The beneficial effects of this scheme are: the drying temperature is set to 80-120°C, and the drying time is set to 6-24h, which can remove the No. 1 organic solvent and the mixed solvent, and prevent the crude activated carbon obtained in S2 from containing the mixed solvent, which affects the operation in S3; and prevent the activated carbon with extremely low impurity content obtained in S3 from containing the No. 1 organic solvent, which affects the operation in S4. If the drying temperature is too high, the structure of the activated carbon will be destroyed. If the temperature is too low, the drying time will be too long or the drying will be incomplete.

[0024] Furthermore, the thermal activation treatment process in S4 is: heating the activated carbon with extremely low impurity content obtained in S3 under the condition of a mixture of any one or more gases of inert gas, water vapor and carbon dioxide, the heating temperature is 600-1000°C, and the reaction time is 1-4h.

[0025] The beneficial effects of this solution are as follows: this technical solution is to perform thermal activation treatment on the activated carbon with extremely low impurity content obtained in S3 under the conditions of 600-1000°C. If the temperature is too high, it will cause the collapse of the activated carbon pore structure, and activated carbon suitable for supercapacitors cannot be obtained. If the temperature is too low, the activation effect will not be achieved. At this temperature, thermal activation treatment is performed on the activated carbon with extremely low impurity content obtained in S3, which can remove excess oxygen-containing functional groups, surface defects and a small amount of pore-clogging substances on the surface of the activated carbon, so that the activated carbon structure can be restored.

[0026] Furthermore, the inert gas in S4 is any one of N2 and Ar.

[0027] The beneficial effect of this solution is that if chemical reagents are used to thermally activate the activated carbon with extremely low impurity content obtained in S3, new impurities will be introduced into the activated carbon, and the activated carbon needs to be decontaminated again, which increases the operation process. However, the present technical solution uses inert gas to thermally activate the activated carbon with extremely low impurity content obtained in S3 under high temperature conditions, which will not introduce new impurities into the activated carbon and is simple to operate.

[0028] Furthermore, the heating device in S4 is any one of a microwave heating furnace and an electric heating furnace.

[0029] The beneficial effect of this scheme is that by heating the activated carbon with extremely low impurity content obtained in S3 through a microwave heating furnace or an electric heating furnace, excessive oxygen-containing functional groups, surface defects, and a small amount of blocked pore materials on the surface of the activated carbon can be removed, so that the activated carbon structure can be restored to obtain high-quality regenerated activated carbon.

[0030] The present invention also provides another technical solution, an application of supercapacitor activated carbon material, wherein the high-quality regenerated activated carbon prepared by the method for recovering and regenerating supercapacitor activated carbon material according to any one of claims 1 to 9 is used for supercapacitors.

[0031] The beneficial effects of this solution are: by recycling and regenerating the activated carbon materials in retired supercapacitors and reusing them in supercapacitors, on the one hand, it can reduce the manufacturing cost of supercapacitors and alleviate the pressure of resource shortages; on the other hand, it can prevent environmental pollution and promote the healthy development of the supercapacitor industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Nitrogen adsorption and desorption test curves of the high-quality regenerated activated carbon prepared in Examples 1-6 and the fresh supercapacitor activated carbon A provided in the comparative example;

[0033] Figure 2Raman spectra of the high-quality regenerated activated carbons prepared in Examples 1-6 and the fresh supercapacitor activated carbon A provided in the comparative example;

[0034] Figure 3 The life test results of cylindrical supercapacitors assembled with high-quality regenerated activated carbon prepared in Examples 1-6 and cylindrical supercapacitors assembled with fresh supercapacitor activated carbon A provided in the comparative example at 65°C and 3.0V constant voltage conditions are shown.

[0035] Figure 4 Graph showing the change in leakage current of the cylindrical supercapacitors assembled with high-quality regenerated activated carbon prepared in Examples 1-6 and the cylindrical supercapacitor assembled with activated carbon A for fresh supercapacitors provided in the comparative example after 96 hours at an initial voltage of 3.0 V. DETAILED DESCRIPTION

[0036] The following is further described in detail through specific implementation methods:

[0037] Example 1

[0038] A method for recovering and regenerating supercapacitor activated carbon material comprises the following steps:

[0039] S1: Fully discharge three 505g retired supercapacitors for 24 hours. After discharge, disassemble them and cut the electrode plates into small pieces of 1-10 mm. In this embodiment, the electrode plates are cut into small pieces of 5 mm.

[0040] S2: Immerse the electrode plate obtained in S1 in a mixed solvent, wherein the mass ratio of the electrode plate to the mixed solvent is 1:20-1:5, and the formed mixture is heated to 60-200°C in a sealed reactor and maintained at a pressure of 0.3-2Mpa, react for 2-12h, and then ultrasonically treated for 10-60min, with an ultrasonic power of 100-600W, and centrifugally separate the aluminum foil fragments and the crude activated carbon product, and then dry the crude activated carbon product at a drying temperature of 80-120°C and a drying time of 6-24h to separate the aluminum foil and the crude activated carbon product. Repeat the above operation 1-3 times, and the mixed solvent can be recycled and reused; in this embodiment, the mass ratio of the electrode plate to the mixed solvent is 1:5, the heating temperature of the mixture is 60°C, the pressure is maintained at 0.3Mpa, the reaction time is 6h, the ultrasonic treatment time is 20min, the ultrasonic power is 400W, the drying temperature is 100°C, the drying time is 12h, and the above operation is repeated 2 times;

[0041] S3: The crude activated carbon obtained in S2 is added to an organic solvent No. 1, wherein the mass ratio of the crude activated carbon to the organic solvent No. 1 is 1:20-1:3. Under a negative pressure of 100-1000 Pa, the formed mixture is heated to 20-60° C., immersed for 4-24 hours, and then ultrasonically treated for 20-60 minutes, with an ultrasonic power of 300-600 W. Finally, centrifugation and drying are performed, with a drying temperature of 80-120° C. and a drying time of 6-24 hours to obtain activated carbon with an extremely low impurity content. The above operation is repeated 1-3 times. In this embodiment, the mass ratio of the crude activated carbon to the organic solvent No. 1 is 1:3, the negative pressure is 100 Pa, the heating temperature is 30° C., the immersion time is 12 hours, the ultrasonic treatment time is 30 minutes, the ultrasonic power is 400 W, the drying temperature is 100° C., the drying time is 10 hours, and the above operation is repeated once.

[0042] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon; the thermal activation treatment process is: under the condition of a mixture of any one or more gases of inert gas, water vapor and carbon dioxide, the activated carbon with extremely low impurity content obtained in S3 is placed in a microwave heating furnace or an electric heating furnace for heating, the heating temperature is 600-1000°C, and the reaction time is 1-4h, wherein the inert gas is any one of N2 and Ar; in this embodiment, the heating temperature is 600°C, the reaction time is 2h, the heating is carried out under N2 conditions, and the heating equipment is a microwave heating furnace.

[0043] Wherein: the mixed solvent in S2 is water or a combination of water and organic solvent No. 2, and the mass ratio of water to organic solvent No. 2 is 1:0-100:1, wherein organic solvent No. 2 is any one of ethanol, acetone and isopropanol. In this embodiment, the mixed solvent is a mixed solvent of water and ethanol, wherein the mass ratio of water to ethanol is 1:2.

[0044] The No. 1 organic solvent in S3 is any one of ethylene carbonate, propylene carbonate, acetonitrile, ethyl ether and methyl ethyl ether, or a mixture of several of them. In this embodiment, the No. 1 organic solvent is propylene carbonate.

[0045] Example 2

[0046] A method for recovering and regenerating supercapacitor activated carbon material comprises the following steps:

[0047] S1: Three 505g retired supercapacitors were fully discharged for 24 hours. After discharge, they were disassembled and the electrode plates were cut into 6mm pieces.

[0048] S2: Immerse the electrode sheet obtained in S1 in water, wherein the mass ratio of the electrode sheet to water is 1:10. The resulting mixture is heated to 80°C in a sealed reactor and maintained at a pressure of 0.5 MPa for 4 hours. The mixture is then ultrasonically treated for 10 minutes at a power of 200 W. The aluminum foil fragments and the crude activated carbon are centrifugally separated. The crude activated carbon is then dried at a drying temperature of 80°C for 24 hours to separate the aluminum foil and the crude activated carbon. Repeat the above operation three times.

[0049] S3: The crude activated carbon obtained in S2 is added to propylene carbonate, wherein the mass ratio of the crude activated carbon to propylene carbonate is 1:5. The resulting mixture is heated to 60°C under a negative pressure of 500 Pa, immersed for 15 hours, and then subjected to ultrasonic treatment for 40 minutes at an ultrasonic power of 300 W. Finally, the mixture is centrifuged and dried at a drying temperature of 120°C for 6 hours to obtain activated carbon with an extremely low impurity content. The above operation is repeated once;

[0050] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon; the thermal activation treatment process is: under Ar conditions, the activated carbon with extremely low impurity content obtained in S3 is placed in a microwave heating furnace for heating, the heating temperature is 800°C, and the reaction time is 4 hours.

[0051] Example 3

[0052] A method for recovering and regenerating supercapacitor activated carbon material comprises the following steps:

[0053] S1: Three 505g retired supercapacitors were fully discharged for 24 hours. After discharge, they were disassembled and the electrode plates were cut into 5mm pieces.

[0054] S2: Immerse the electrode plate obtained in S1 in a mixed solvent of water and acetone, wherein the mass ratio of water to acetone is 100:1, and the mass ratio of the electrode plate to the mixed solvent is 1:20. The formed mixture is heated to 120°C in a sealed reactor and maintained at a pressure of 1 MPa for 10 hours. The mixture is then ultrasonically treated for 40 minutes at a power of 500 W. The aluminum foil fragments and the crude activated carbon are centrifugally separated. The crude activated carbon is then dried at a drying temperature of 100°C for 6 hours to separate the aluminum foil and the crude activated carbon. Repeat the above operation 3 times.

[0055] S3: The crude activated carbon obtained in S2 is added to an organic solvent mixed with propylene carbonate and acetonitrile, wherein the mass ratio of propylene carbonate to acetonitrile is 2:1, and the mass ratio of the crude activated carbon to the organic solvent mixed with propylene carbonate and acetonitrile is 1:10. The resulting mixture is heated to 50° C. under a negative pressure of 1000 Pa, immersed for 15 hours, and then subjected to ultrasonic treatment for 20 minutes with an ultrasonic power of 500 W. Finally, the mixture is centrifuged and dried at a drying temperature of 120° C. for 10 hours to obtain activated carbon with an extremely low impurity content. The above operation is repeated twice;

[0056] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon; the thermal activation treatment process is: in a mixed atmosphere of N2 and water vapor, the activated carbon with extremely low impurity content obtained in S3 is placed in a microwave heating furnace for heating, the heating temperature is 700°C, the reaction time is 1 hour, and the mass ratio of N2 to water vapor is 5:1.

[0057] Example 4

[0058] A method for recovering and regenerating supercapacitor activated carbon material comprises the following steps:

[0059] S1: Three 505g retired supercapacitors were fully discharged for 24 hours. After discharge, they were disassembled and the electrode plates were cut into 5mm pieces.

[0060] S2: Immerse the electrode plate obtained in S1 in a mixed solvent of water and isopropyl alcohol, wherein the mass ratio of water to isopropyl alcohol is 10:1, and the mass ratio of the electrode plate to the mixed solvent is 1:15. The formed mixture is heated to 200°C in a sealed reactor and maintained at a pressure of 2 MPa for 12 hours. The mixture is then ultrasonically treated for 60 minutes at a power of 600 W. The aluminum foil fragments and the crude activated carbon are centrifugally separated. The crude activated carbon is then dried at a drying temperature of 120°C for 10 hours to separate the aluminum foil and the crude activated carbon. Repeat the above operation twice.

[0061] S3: The crude activated carbon obtained in S2 is added to a mixed solvent of methyl ethyl ether and acetonitrile, wherein the mass ratio of methyl ethyl ether to acetonitrile is 3:1, and the mass ratio of the crude activated carbon to the mixed solvent of methyl ethyl ether and acetonitrile is 1:15. The resulting mixture is heated to 60°C under a negative pressure of 200 Pa, immersed for 24 hours, and then subjected to ultrasonic treatment for 60 minutes with an ultrasonic power of 600 W. Finally, the mixture is centrifuged and dried at a drying temperature of 120°C and a drying time of 10 hours to obtain activated carbon with an extremely low impurity content. The above operation is repeated 3 times;

[0062] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon; the thermal activation treatment process is: under carbon dioxide gas conditions, the activated carbon with extremely low impurity content obtained in S3 is placed in a microwave heating furnace for heating, the heating temperature is 800°C, and the heating time is 3 hours.

[0063] Example 5

[0064] A method for recovering and regenerating supercapacitor activated carbon material comprises the following steps:

[0065] S1: Three 505g retired supercapacitors were fully discharged for 24 hours. After discharge, they were disassembled and the electrode plates were cut into 5mm pieces.

[0066] S2: Immerse the electrode plate obtained in S1 in a mixed solvent of water and ethanol, wherein the mass ratio of water to ethanol is 3:1, and the mass ratio of the electrode plate to the mixed solvent is 1:15. The formed mixture is heated to 160°C in a sealed reactor and maintained at a pressure of 1.5 MPa for 12 hours. The mixture is then ultrasonically treated for 30 minutes at a power of 600 W. The aluminum foil fragments and the crude activated carbon are centrifuged and then dried at a drying temperature of 120°C for 8 hours to separate the aluminum foil and the crude activated carbon. Repeat the above operation 3 times.

[0067] S3: The crude activated carbon obtained in S2 is added to an organic solvent mixture of diethyl ether and acetonitrile, wherein the mass ratio of diethyl ether to acetonitrile is 3:1, and the mass ratio of the crude activated carbon to the organic solvent mixture of propylene carbonate and acetonitrile is 1:8. The resulting mixture is heated to 60°C under a negative pressure of 300 Pa, immersed for 24 hours, and then subjected to ultrasonic treatment for 30 minutes at an ultrasonic power of 600 W. Finally, the mixture is centrifuged and dried at a drying temperature of 120°C for 8 hours to obtain activated carbon with an extremely low impurity content. The above operation is repeated twice;

[0068] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon; the thermal activation treatment process is: in a mixed atmosphere of Ar and carbon dioxide, the activated carbon with extremely low impurity content obtained in S3 is placed in a microwave heating furnace for heating, the heating temperature is 900°C, the heating time is 2 hours, and the mass ratio of Ar to carbon dioxide is 6:1.

[0069] Example 6

[0070] A method for recovering and regenerating supercapacitor activated carbon material comprises the following steps:

[0071] S1: Three 505g retired supercapacitors were fully discharged for 24 hours. After discharge, they were disassembled and the electrode plates were cut into 5mm pieces.

[0072] S2: Immerse the electrode plate obtained in S1 in a mixed solvent of water and acetone, wherein the mass ratio of water to acetone is 8:1, and the mass ratio of the electrode plate to the mixed solvent is 1:8. The formed mixture is heated to 180°C in a sealed reactor and maintained at a pressure of 1.8 MPa for 8 hours. The mixture is then ultrasonically treated for 40 minutes at a power of 400 W. The aluminum foil fragments and the crude activated carbon are centrifuged and then dried at a drying temperature of 110°C for 16 hours to obtain the aluminum foil and the crude activated carbon. Repeat the above operation 3 times.

[0073] S3: The crude activated carbon obtained in S2 is added to an organic solvent mixed with propylene carbonate and ethyl methyl ether, wherein the mass ratio of propylene carbonate and ethyl methyl ether is 1:1, and the mass ratio of the crude activated carbon to the organic solvent mixed with propylene carbonate and ethyl methyl ether is 1:6. The resulting mixture is heated to 50° C. under a negative pressure of 400 Pa, immersed for 18 hours, and then subjected to ultrasonic treatment for 50 minutes with an ultrasonic power of 500 W. Finally, the mixture is centrifuged and dried at a drying temperature of 120° C. for 24 hours to obtain activated carbon with an extremely low impurity content. The above operation is repeated 3 times;

[0074] S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain high-quality regenerated activated carbon; the thermal activation treatment process is: in a mixed atmosphere of N2, water vapor and carbon dioxide, the activated carbon with extremely low impurity content obtained in S3 is placed in a microwave heating furnace for heating, the heating temperature is 1000°C, the heating time is 1 hour, wherein the mass ratio of N2, water vapor and carbon dioxide is 10:1:1.

[0075] The high-quality regenerated activated carbon prepared in Examples 1-6 can be reused in supercapacitors.

[0076] Comparative Example

[0077] A new activated carbon A for supercapacitors that is widely used in the market.

[0078] The physical and chemical properties of the high-quality regenerated activated carbons prepared in Examples 1-6 and the fresh activated carbon A for supercapacitors provided in the comparative example were analyzed. The analysis results are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] It can be seen from Table 1 that the conductivity of Example 6 is significantly higher than that of the comparative example, and the ash content and metal element content of Example 6 are lower than those of the comparative example. The tap density of Example 6 is close to that of the comparative example. It can be seen that the physicochemical properties of the high-quality regenerated activated carbon prepared in Example 6 are better than those of the comparative example, and the physicochemical properties of the high-quality regenerated activated carbon prepared in Examples 1-5 are also comparable to those of the comparative example. It can be seen that the high-quality regenerated activated carbon prepared in Examples 1-6 can be directly used in supercapacitors, realizing the recycling and reuse of activated carbon, reducing the manufacturing cost of supercapacitors, and at the same time, reducing environmental pollution and promoting the healthy development of the supercapacitor industry.

[0083] The high-quality regenerated activated carbon prepared in Examples 1-6 and the fresh supercapacitor activated carbon A in the comparative example were subjected to gas adsorption and desorption tests in a nitrogen environment. The test results are shown in FIG. Figure 1 As shown by Figure 1 It can be seen that the specific surface area of the high-quality regenerated activated carbon prepared in Examples 1-6 has been basically restored or even improved.

[0084] The high-quality regenerated activated carbons prepared in Examples 1-6 and the fresh supercapacitor activated carbon A in the comparative example were tested by Raman spectrometer. Figure 2 It can be seen that the D peak and G peak of Examples 1-6 and the comparative example are relatively close, wherein the D peak represents the defect structure peak and the G peak represents the graphitized structure peak, indicating that the graphitized structures of Examples 1-6 and the comparative example are close, and the conductive properties of the high-quality regenerated activated carbon prepared in Examples 1-6 have been restored.

[0085] The high-quality regenerated activated carbon prepared in Examples 1-6 and the fresh supercapacitor activated carbon A in the comparative example were assembled into cylindrical supercapacitors, and their electrochemical properties were tested. Specifically, the high-quality regenerated activated carbon prepared in Examples 1-6 and the fresh supercapacitor activated carbon A in the comparative example were stirred and dispersed with a binder, a conductive agent, a solvent, etc., and then coated on aluminum foil to prepare an electrode material, which was then assembled into a cylindrical supercapacitor.

[0086] The voltage, internal resistance and capacitance of the cylindrical supercapacitors assembled with the high-quality regenerated activated carbon prepared in Examples 1-6 and the cylindrical supercapacitor assembled with the fresh supercapacitor activated carbon A provided in the comparative example were tested, and the test results are shown in Table 2.

[0087] Table 2

[0088]

[0089] As can be seen from Table 2, the voltage, capacitance, DC internal resistance and AC internal resistance of the cylindrical supercapacitors assembled with the high-quality regenerated activated carbon prepared in Examples 1-6 are close to those of the cylindrical supercapacitors assembled with the fresh activated carbon A for supercapacitors provided in the comparative example. Therefore, it can be seen that the high-quality regenerated activated carbon prepared in Examples 1-6 can be directly used in supercapacitors.

[0090] The life of the cylindrical supercapacitors assembled with high-quality regenerated activated carbon prepared in Examples 1-6 and the cylindrical supercapacitor assembled with fresh supercapacitor activated carbon A provided in the comparative example were tested at 65°C and 3.0V constant voltage. The test results are shown in Table 1. Figure 3 .

[0091] Depend on Figure 3 It can be seen that as the aging time increases, the capacitance retention rates of Examples 1-6 are all higher than that of the comparative example. Therefore, it can be seen that the performance of the high-quality regenerated activated carbon prepared in Examples 1-6 has been restored.

[0092] At an initial voltage of 3.0 V, after 96 hours, the leakage current performance of the cylindrical supercapacitors assembled with high-quality regenerated activated carbon prepared in Examples 1-6 and the cylindrical supercapacitor assembled with fresh supercapacitor activated carbon A provided in the comparative example were tested. The test results are shown in Tables 3 and Figure 4 .

[0093] Table 3

[0094]

[0095]

[0096] From Table 3 and Figure 4 It can be seen that the leakage current of Examples 1-6 is smaller than that of the comparative example, indicating that the smaller the self-consumption current of the cylindrical supercapacitor assembled with high-quality regenerated activated carbon prepared in Examples 1-6, the better the performance of the cylindrical supercapacitor assembled with high-quality regenerated activated carbon prepared in Examples 1-6.

[0097] In summary, the physical and chemical properties, specific surface area, and graphitized structure of the high-quality regenerated activated carbon prepared in Examples 1-6 have been restored. By testing the electrochemical properties of the cylindrical supercapacitors assembled with the high-quality regenerated activated carbon prepared in Examples 1-6, it was found that the voltage, capacitance, DC internal resistance, and AC internal resistance of the cylindrical supercapacitors assembled with the high-quality regenerated activated carbon prepared in Examples 1-6 were close to those of the cylindrical supercapacitors assembled with the fresh activated carbon A for supercapacitors provided in the comparative example, and their lifespan and leakage current performance were better than those of the cylindrical supercapacitors assembled with the fresh activated carbon A for supercapacitors provided in the comparative example. It can be seen that the high-quality regenerated activated carbon prepared in Examples 1-6 can be directly applied to supercapacitors, realizing the recycling and reuse of activated carbon, reducing the manufacturing cost of supercapacitors, and at the same time, reducing environmental pollution and promoting the healthy development of the supercapacitor industry.

[0098] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A method for recovering and regenerating activated carbon materials for supercapacitors, characterized by: The following steps are involved: S1: Disassemble the retired supercapacitor, remove the electrode plates, and cut the electrode plates into small pieces of 1-10mm; S2: Immerse the electrode sheet obtained in S1 in a mixed solvent, wherein the mass ratio of the electrode sheet to the mixed solvent is 1:20-1:5, and react the resulting mixture under high temperature and high pressure conditions of 60-200°C and 0.3-2 MPa for 2-12 hours, then perform ultrasonic treatment for 10-60 minutes, with the ultrasonic power being 100-600W. Finally, perform centrifugal separation and drying to separate the aluminum foil and the crude activated carbon, and repeat the above operation 1-3 times; S3: adding the crude activated carbon obtained in S2 to an organic solvent No. 1, wherein the mass ratio of the crude activated carbon to the organic solvent No. 1 is 1:20-1:3, heating the mixture of the crude activated carbon and the organic solvent No. 1 to 20-60° C. under negative pressure, impregnating for 4-24 hours, and then ultrasonically treating for 20-60 minutes at an ultrasonic power of 300-600 W. Finally, centrifuging and drying are performed to obtain activated carbon with an extremely low impurity content, and the above operation is repeated 1-3 times; the organic solvent No. 1 is any one or a mixture of ethylene carbonate, propylene carbonate, acetonitrile, ether, and methyl ethyl ether; S4: The activated carbon with extremely low impurity content obtained in S3 is subjected to thermal activation treatment to obtain regenerated activated carbon.

2. The method for recovering and regenerating supercapacitor activated carbon material according to claim 1, characterized in that: The mixed solvent in S2 is water or a combination of water and a second organic solvent, and the mass ratio of water to the second organic solvent is 1:0-100:1, wherein the second organic solvent is any one of ethanol, acetone and isopropanol.

3. The method for recovering and regenerating supercapacitor activated carbon material according to claim 2, characterized in that: The negative pressure in S3 is 100-1000Pa.

4. The method for recovering and regenerating supercapacitor activated carbon material according to claim 3, characterized in that: The drying temperature in S2 and S3 is both 80-120°C, and the drying time is both 6-24h.

5. The method for recovering and regenerating supercapacitor activated carbon material according to claim 4, characterized in that: The thermal activation treatment process in S4 is: heating the activated carbon with extremely low impurity content obtained in S3 under the condition of a mixture of any one or more gases of inert gas, water vapor and carbon dioxide, the heating temperature is 600-1000°C, and the reaction time is 1-4h.

6. The method for recovering and regenerating supercapacitor activated carbon material according to claim 5, characterized in that: The inert gas in S4 is either N2 or Ar.

7. The method for recovering and regenerating supercapacitor activated carbon material according to claim 6, characterized in that: The heating device in S4 is any one of a microwave heating furnace and an electric heating furnace.

8. An application of activated carbon material for supercapacitors, characterized by: The regenerated activated carbon prepared by the method for recovering and regenerating supercapacitor activated carbon material according to any one of claims 1 to 7 is used for supercapacitors.

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