Preparation method of anti-agglomeration super capacitor dry electrode

Abstract

The invention provides an anti-agglomeration supercapacitor dry electrode preparation method, and belongs to the technical field of supercapacitor dry electrodes, the preparation method comprises the following steps: S1, mixing an active carbon material, a conductive agent and PTFE to obtain a premixed material; s2, adding the premixed material into a jet mill for fibration treatment to obtain a fibration material; s3, compacting the fiberized material, then carrying out crushing treatment, and carrying out high-temperature rolling treatment on the crushed powder to obtain a self-supporting carbon film; and S4, compounding the self-supporting carbon film and the carbon-coated aluminum foil to obtain the anti-agglomeration super capacitor dry electrode. According to the dry electrode preparation method provided by the invention, the problem of uneven distribution caused by PTFE fibration degree difference can be solved, the film forming uniformity is effectively improved, and the prepared super capacitor dry electrode has relatively high electrochemical stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of supercapacitor dry electrodes, and in particular relates to a method for preparing a supercapacitor dry electrode that is anti-agglomeration and agglomeration. Background Art

[0002] At present, the structures of supercapacitors are mainly button-shaped and cylindrical. Among them, the cylindrical structure has become the mainstream due to its high energy density and wide application scenarios. Its structure is mainly composed of electrodes, diaphragms, shells and electrolytes filled inside. Among them, electrodes are the core components of supercapacitors and play a decisive role in the performance of supercapacitors.

[0003] The production methods of supercapacitor electrodes are divided into dry process and wet process. For the dry process, the existing technology focuses more on material formulation and calendering parameters, and there is less research on the pretreatment of the mixture after fiberization and the component distribution binder in the dry mixture. In fact, fiberization treatment is a more core step, which determines the performance and processing efficiency of the subsequent steps of preparing electrode electrodes.

[0004] During the fiberization process, the mixture is easily agglomerated due to shear force, which affects the uniformity of film formation. At the same time, the difference in the degree of PTFE fiberization leads to uneven distribution of PTFE fibers, which also affects the uniformity of film formation. Not only will the electrochemical performance of the carbon film material output by the equipment be reduced, but it will also affect production efficiency. Summary of the Invention

[0005] In order to solve the problems existing in the background technology, the present invention provides a method for preparing a supercapacitor dry electrode that prevents agglomeration and caking. This method can solve the problem of uneven distribution caused by differences in the degree of PTFE fiberization, effectively improve the film formation uniformity, and enable the prepared supercapacitor dry electrode to have higher electrochemical performance.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried and then placed in a ball mill for ball milling to obtain a mixed powder. The mixed powder and PTFE are added together in a high-speed mixer and stirred at high speed to obtain a premixed material, wherein the activated carbon material is prepared by mixing gelatin, tannic acid and carboxylated carbon nanotubes and then calcining at high temperature; S2 fiberization stage: The premixed material obtained in step S1 is added to the feeder of the airflow mill, feeding according to 75-100% of the processing capacity of the equipment, controlling the operating pressure and temperature of the equipment, and fiberizing the material to obtain a fiberized material; S3 re-crushing and rolling stage: The fiberized material of step S2 is compacted and then added to the crushing equipment for crushing to obtain a crushed powder, which is then subjected to high-temperature rolling to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film obtained in step S3 is composited with carbon-coated aluminum foil under high temperature and high pressure to obtain a supercapacitor dry electrode that is anti-agglomeration.

[0007] Furthermore, the preparation of the activated carbon material in step S1 includes the following steps: A1. Add 5 parts gelatin and 2-3 parts tannic acid, by weight, to 90-110 parts boric acid solution (the concentration of the boric acid solution is 0.8-1.2%), heat to 60-80°C, and stir for 20-40 minutes to obtain a pretreated gelatin solution. A2. Add 20-30 parts by mass of a 0.4-0.6% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 2-4 hours, then heat to boiling, evaporate the solvent, and dry to obtain modified gelatin; A3. The modified gelatin obtained in step A2 is heated to 800-1000° C. at a heating rate of 3-10° C. / min under inert gas protection, calcined at a constant temperature for 3-5 hours, and naturally cooled to room temperature to obtain an activated carbon material.

[0008] Furthermore, in step S1, the conductive agent is one or a mixture of two or more of acetylene black, SuperP and Ketjen black ECP.

[0009] Furthermore, in step S1, the mass of the conductive agent accounts for 8-12% of the total mass of the mixed powder, and the mass of PTFE accounts for 6-10% of the total mass of the premixed material.

[0010] Furthermore, in the drying process in step S1, the drying temperature is 100-180° C., the drying time is 12-24 hours, and the material is dried until the moisture content is below 1%.

[0011] Furthermore, during the high-speed stirring process in step S1, the stirring temperature is 10-20° C., the stirring speed is 30-40 m / s, and the stirring time is 20-40 min.

[0012] Furthermore, in step S2, the working pressure of the air flow mill is 0.5-0.9 MPa, and the working temperature is 60-100°C.

[0013] Furthermore, in step S3, the compaction pressure is 2-10 MPa, the rolling pressure in the high-temperature rolling is 0.3-0.8 t / cm, the rolling temperature is 140-190° C., and the differential speed ratio of the two rollers is 1:2.

[0014] Furthermore, in the crushing process in step S3, the fibrous material is firstly cut into flocculent material with a diameter of 1-5 mm, and then the flocculent material is crushed into powdery material.

[0015] Furthermore, before lamination in step S4, the self-supporting carbon film and the carbon-coated aluminum foil are preheated at a temperature of 110-150°C, and the lamination method is roller pressing at a pressure of 0.2-0.5 t / cm and a temperature of 140-180°C.

[0016] This application has the following beneficial effects: 1. Each step of this preparation method has undergone precise parameter control. From the drying, ball milling and stirring of the raw materials, to the fiberization treatment, re-crushing and roller pressing, and finally to the composite preparation, each link is closely coordinated to solve the uneven distribution problem caused by differences in the degree of PTFE fiberization, effectively improve the uniformity of film formation, and ensure the quality and stable performance of the final product.

[0017] 2. By compacting the fibrous material and then re-crushing it, the materials can be redistributed and combined to achieve uniform bonding between the materials, avoid the adverse effects of the primary film-forming process, and improve the uniformity of the film. In addition, re-crushing after compaction can increase the tap density, enhance the bonding performance between the materials, make the carbon film have better integrity, better bond with the carbon-coated aluminum foil, and improve the overall stability of the electrode.

[0018] 3. In the modification of the carbon film, carboxylated carbon nanotubes are introduced to enable them to interact with the hydroxyl groups in gelatin, thereby changing the microstructure and surface properties of the carbon film. This modification not only helps to improve the conductive properties of the carbon film, but also enhances its bonding properties with other materials, thereby improving the integrity and stability of the supercapacitor dry electrode. In addition, carbon nanotubes are a material with highly controllable arrays and easy orientation. After fiberization, they are re-crushed, which can improve the orientation of carbon nanotubes and obtain carbon nanotube macro-aggregates at the same time, giving them good film-forming properties. Ultimately, the carbon film has a more stable structure and a more complete conductive network, further improving the electrochemical stability of the supercapacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 , SEM image of the supercapacitor dry electrode obtained in Example 1 of the present invention; Figure 2 , the high temperature load performance of the cylindrical supercapacitor prepared by assembling the supercapacitor dry electrode pieces obtained in Example 1 of the present invention at 3.0V / 70℃. DETAILED DESCRIPTION

[0020] The present application is further described in detail below with reference to the embodiments.

[0021] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available. Example 1

[0022] A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried at a drying temperature of 140°C for 18 hours until the moisture content of the materials is less than 1%. The materials are then placed in a ball mill and ball-milled for 30 minutes to obtain a mixed powder. The mixed powder and PTFE are added to a high-speed mixer and stirred at a high speed of 15°C, a stirring speed of 35m / s, and a stirring time of 30 minutes to obtain a premixed material, wherein the conductive agent is acetylene black, the mass of the conductive agent accounts for 10% of the total mass of the mixed powder, and the mass of PTFE accounts for 8% of the total mass of the premixed material; S2 fiberization stage: The premixed material obtained in step S1 was added to the feeder of the airflow mill, and the feed was carried out at 85% of the processing capacity of the equipment. The airflow mill had an operating pressure of 0.7 MPa and an operating temperature of 80 ° C. The material was fiberized to obtain a fiberized material. S3. Re-crushing and rolling stage: The fibrous material of step S2 is compacted at a compaction pressure of 6 MPa and then added to the crushing equipment. The fibrous material is first cut into flocculent materials with a diameter of 1-5 mm, and then the flocculent materials are crushed into powdery materials to obtain crushed powders. The crushed powders are subjected to high-temperature rolling treatment at a rolling pressure of 0.5 t / cm, a rolling temperature of 165 ° C, and a differential speed ratio of the two rollers of 1:2 to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film and the carbon-coated aluminum foil are preheated at 130°C, and then the self-supporting carbon film and the carbon-coated aluminum foil are roll-compounded under high temperature and high pressure at a rolling pressure of 0.35t / cm and a rolling temperature of 160°C to obtain a supercapacitor dry electrode that is anti-agglomeration and caking.

[0023] The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 2.5 parts tannic acid, by weight, to 100 parts boric acid solution (1.0% concentration), heat to 70°C, and stir for 30 minutes to obtain a pretreated gelatin solution. A2. Add 25 parts by mass of a 0.5% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 3 hours, then heat to boiling, evaporate to remove the solvent, and dry to obtain modified gelatin, wherein the carboxylated carbon nanotube dispersion is a dispersion of carboxylated carbon nanotubes in DMF; A3. The modified gelatin obtained in step A2 was heated to 900° C. at a heating rate of 5° C. / min under nitrogen protection, calcined at a constant temperature for 4 hours, and naturally cooled to room temperature to obtain an activated carbon material. Example 2

[0024] A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried at a temperature of 100°C for 24 hours until the moisture content of the materials is less than 1%. The materials are then placed in a ball mill and ball milled for 30 minutes to obtain a mixed powder. The mixed powder and PTFE are added to a high-speed mixer and stirred at a high speed of 10°C, a stirring speed of 30m / s, and a stirring time of 40 minutes to obtain a premixed material, wherein the conductive agent is SuperP, the mass of the conductive agent accounts for 12% of the total mass of the mixed powder, and the mass of PTFE accounts for 10% of the total mass of the premixed material; S2 fiberization stage: the premixed material obtained in step S1 is added to the feeder of the airflow mill, feeding according to 100% of the processing capacity of the equipment, the airflow mill operating pressure is 0.5MPa, the operating temperature is 100 ℃, the material is fiberized to obtain a fiberized material; S3. Re-crushing and rolling stage: The fibrous material of step S2 is compacted at a compaction pressure of 2 MPa and then added to the crushing equipment. The fibrous material is first cut into flocculent materials with a diameter of 1-5 mm, and then the flocculent material is crushed into a powder material to obtain a crushed powder. The crushed powder is subjected to high-temperature rolling treatment at a rolling pressure of 0.3 t / cm, a rolling temperature of 140 ° C, and a differential speed ratio of the two rollers of 1:2 to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film and the carbon-coated aluminum foil are preheated at 110°C, and then the self-supporting carbon film and the carbon-coated aluminum foil are roll-compounded under high temperature and high pressure at a rolling pressure of 0.2 t / cm and a rolling temperature of 140°C to obtain a supercapacitor dry electrode that is anti-agglomeration.

[0025] The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 2 parts tannic acid, by weight, to 90 parts boric acid solution (the concentration of the boric acid solution is 0.8%), heat to 60°C, and stir for 40 minutes to obtain a pretreated gelatin solution. A2. Add 20 parts by mass of a 0.4% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 2 hours, then heat to boiling, evaporate to remove the solvent, and dry to obtain modified gelatin, wherein the carboxylated carbon nanotube dispersion is a dispersion of carboxylated carbon nanotubes in DMF; A3. The modified gelatin obtained in step A2 was heated to 800° C. at a heating rate of 10° C. / min under nitrogen protection, calcined at a constant temperature for 5 hours, and naturally cooled to room temperature to obtain an activated carbon material. Example 3

[0026] A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried at a temperature of 180°C for 12 hours until the moisture content of the materials is less than 1%. The materials are then placed in a ball mill and ball milled for 30 minutes to obtain a mixed powder. The mixed powder and PTFE are added to a high-speed mixer and stirred at a high speed of 20°C, a stirring speed of 40 m / s, and a stirring time of 20 minutes to obtain a premixed material, wherein the conductive agent is Ketjen Black ECP, the mass of the conductive agent accounts for 8% of the total mass of the mixed powder, and the mass of PTFE accounts for 6% of the total mass of the premixed material; S2 fiberization stage: The premixed material obtained in step S1 was added to the feeder of the airflow mill, and the feed was carried out at 75% of the processing capacity of the equipment. The airflow mill had an operating pressure of 0.9 MPa and an operating temperature of 60 ° C. The material was fiberized to obtain a fiberized material. S3. Re-crushing and rolling stage: The fibrous material of step S2 is compacted at a compaction pressure of 10 MPa and then added to the crushing equipment. The fibrous material is first cut into flocculent materials with a diameter of 1-5 mm, and then the flocculent materials are crushed into powdery materials to obtain crushed powders. The crushed powders are subjected to high-temperature rolling treatment at a rolling pressure of 0.8 t / cm, a rolling temperature of 190 ° C, and a differential speed ratio of the two rollers of 1:2 to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film and the carbon-coated aluminum foil are preheated at 150°C, and then the self-supporting carbon film and the carbon-coated aluminum foil are roll-compounded under high temperature and high pressure at a rolling pressure of 0.5t / cm and a rolling temperature of 180°C to obtain a supercapacitor dry electrode that is anti-agglomeration.

[0027] The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 3 parts tannic acid, by weight, to 110 parts boric acid solution (1.2% concentration), heat to 80°C, and stir for 20 minutes to obtain a pretreated gelatin solution. A2. Add 30 parts by mass of a 0.6% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 4 hours, then heat to boiling, evaporate to remove the solvent, and dry to obtain modified gelatin, wherein the carboxylated carbon nanotube dispersion is a dispersion of carboxylated carbon nanotubes in DMF; A3. The modified gelatin obtained in step A2 was heated to 800° C. at a heating rate of 3° C. / min under nitrogen protection, calcined at a constant temperature for 5 hours, and naturally cooled to room temperature to obtain an activated carbon material. Example 4

[0028] A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried at a temperature of 100°C for 24 hours until the moisture content of the materials is less than 1%. The materials are then placed in a ball mill and ball-milled for 30 minutes to obtain a mixed powder. The mixed powder and PTFE are added to a high-speed mixer and stirred at a high speed of 20°C, a stirring speed of 30 m / s, and a stirring time of 40 minutes to obtain a premixed material, wherein the conductive agent is acetylene black, the mass of the conductive agent accounts for 10% of the total mass of the mixed powder, and the mass of PTFE accounts for 6% of the total mass of the premixed material; S2 fiberization stage: The premixed material obtained in step S1 is added to the feeder of the airflow mill, feeding according to 80% of the processing capacity of the equipment, the airflow mill has a working pressure of 0.6MPa and an operating temperature of 90°C, and the material is fiberized to obtain a fiberized material; S3. Re-crushing and rolling stage: The fibrous material of step S2 is compacted at a compaction pressure of 5 MPa and then added to the crushing equipment. The fibrous material is first cut into flocculent materials with a diameter of 1-5 mm, and then the flocculent material is crushed into a powder material to obtain a crushed powder. The crushed powder is subjected to high-temperature rolling treatment at a rolling pressure of 0.4 t / cm, a rolling temperature of 150 ° C, and a differential speed ratio of the two rollers of 1:2 to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film and the carbon-coated aluminum foil are preheated at 120°C, and then the self-supporting carbon film and the carbon-coated aluminum foil are roll-compounded under high temperature and high pressure at a rolling pressure of 0.3 t / cm and a rolling temperature of 150°C to obtain a supercapacitor dry electrode that is anti-agglomeration.

[0029] The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 2 parts tannic acid to 110 parts boric acid solution (1% concentration), heat to 60°C, and stir for 40 minutes to obtain a pretreated gelatin solution. A2. Add 30 parts by mass of a 0.5% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 3 hours, then heat to boiling, evaporate to remove the solvent, and dry to obtain modified gelatin, wherein the carboxylated carbon nanotube dispersion is a dispersion of carboxylated carbon nanotubes in DMF; A3. The modified gelatin obtained in step A2 was heated to 1000° C. at a heating rate of 10° C. / min under nitrogen protection, calcined at a constant temperature for 3 hours, and naturally cooled to room temperature to obtain an activated carbon material. Example 5

[0030] A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried at a temperature of 130°C for 18 hours until the moisture content of the materials is less than 1%. The materials are then placed in a ball mill and ball-milled for 30 minutes to obtain a mixed powder. The mixed powder and PTFE are added to a high-speed mixer and stirred at a high speed of 10°C, a stirring speed of 35 m / s, and a stirring time of 40 minutes to obtain a premixed material, wherein the conductive agent is Ketjen Black ECP, the mass of the conductive agent accounts for 9% of the total mass of the mixed powder, and the mass of PTFE accounts for 7% of the total mass of the premixed material; S2 fiberization stage: The premixed material obtained in step S1 is added to the feeder of the airflow mill, and the feed is fed at 90% of the processing capacity of the equipment. The airflow mill has a working pressure of 0.8 MPa and an operating temperature of 70 ° C. The material is fiberized to obtain a fiberized material; S3. Re-crushing and rolling stage: The fibrous material of step S2 is compacted at a compaction pressure of 4 MPa and then added to the crushing equipment. The fibrous material is first cut into flocculent materials with a diameter of 1-5 mm, and then the flocculent material is crushed into a powder material to obtain a crushed powder. The crushed powder is subjected to high-temperature roller pressing treatment at a roller pressure of 0.6 t / cm, a roller temperature of 150 ° C, and a differential speed ratio of the two rollers of 1:2 to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film and the carbon-coated aluminum foil are preheated at 140°C, and then the self-supporting carbon film and the carbon-coated aluminum foil are roll-compounded under high temperature and high pressure at a rolling pressure of 0.4 t / cm and a rolling temperature of 170°C to obtain a supercapacitor dry electrode that is anti-agglomeration.

[0031] The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 2.5 parts tannic acid, by weight, to 100 parts boric acid solution (1.2% concentration), heat to 80°C, and stir for 20 minutes to obtain a pretreated gelatin solution. A2. Add 30 parts by mass of a 0.6% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 2 hours, then heat to boiling, evaporate to remove the solvent, and dry to obtain modified gelatin, wherein the carboxylated carbon nanotube dispersion is a dispersion of carboxylated carbon nanotubes in DMF; A3. The modified gelatin obtained in step A2 was heated to 800° C. at a heating rate of 3° C. / min under nitrogen protection, calcined at a constant temperature for 5 hours, and naturally cooled to room temperature to obtain an activated carbon material. Comparative Example 1

[0032] The difference between this comparative example and Example 1 is that, in the preparation of the activated carbon material, no gelatin was modified, that is, no carboxylated carbon nanotubes were added. The specific contents are as follows: The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 2.5 parts tannic acid, by weight, to 100 parts boric acid solution (1.0% concentration), heat to 70°C, and stir for 30 minutes to obtain a pretreated gelatin solution. A2. Add 25 parts of DMF to the gelatin solution pretreated in step A1, stir for 3 hours, then heat to boiling, evaporate to remove the solvent, and dry to obtain modified gelatin; A3. The modified gelatin obtained in step A2 was heated to 900° C. at a heating rate of 5° C. / min under nitrogen protection, calcined at a constant temperature for 4 hours, and naturally cooled to room temperature to obtain an activated carbon material. Comparative Example 2

[0033] The only difference between this comparative example and Example 1 is that in the method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, no crushing process is performed in step S3. The specific contents are as follows: S3 re-crushing and rolling stage: The fiberized material of step S2 was subjected to high temperature rolling treatment, the rolling pressure was 0.5t / cm, the rolling temperature was 165 ℃, the differential speed ratio of the two rollers was 1: 2, to obtain a self-supporting carbon film; Comparative Example 3

[0034] The only difference between this comparative example and Example 1 is that, in the preparation of the activated carbon material, the activated carbon material is not modified, and in the method for preparing the supercapacitor dry electrode for preventing agglomeration and caking, no crushing treatment is performed in step S3. Proven effectiveness

[0035] The dry electrodes prepared in the embodiment and comparative example were assembled to prepare a 3.0V / 10F (φ8*25) cylindrical supercapacitor. The high-temperature load performance of the cylindrical supercapacitor at 3.0V / 70°C was tested, and its internal resistance growth rate and capacity retention rate after 1000h of high-temperature load were tested.

[0036] Table 1

[0037] By analyzing Examples 1-5 and Comparative Examples 1-3, and combining the data in Table 1, it can be seen that the supercapacitor dry electrode prepared by the anti-agglomeration and agglomeration supercapacitor dry electrode preparation method provided by the present invention has a capacity retention rate and an internal resistance growth rate of less than 200% after 1000 hours of high-temperature load, and a capacity retention rate of more than 78.3%. It can be seen that the supercapacitor dry electrode prepared by the preparation method of the present invention has high electrochemical stability, can effectively reduce the increase rate of the capacitor internal resistance, improve the capacity retention rate, and extend the service life of the capacitor. The specific analysis is as follows: It can be seen from Comparative Example 1 and Example 1 that by modifying the gelatin, the internal resistance growth rate of the supercapacitor is reduced and the capacity retention rate is increased from 76.3% to 79.2%, indicating that the addition of carboxylated carbon nanotubes to the pretreated gelatin can improve the electrochemical stability of the electrode material, effectively control the internal resistance growth of the supercapacitor, and improve the capacity retention rate of the supercapacitor; It can be seen from Comparative Example 2 and Example 1 that by crushing the fiberized material, the internal resistance growth rate of the supercapacitor is reduced, and the capacity retention rate is increased from 73.7% to 79.2%, indicating that the crushing process of the fiberized material can improve the electrochemical stability of the electrode material, effectively control the internal resistance growth of the supercapacitor, and improve the capacity retention rate of the supercapacitor; A comprehensive analysis of comparative examples 1-3 and example 1 shows that the modification of gelatin and the crushing process of fibrous materials can improve the electrochemical stability of the electrode material, effectively control the internal resistance growth of the supercapacitor, and improve the capacity retention rate of the supercapacitor. In addition, when the modified gelatin and the crushing process of fibrous materials are used in combination, the increase in the capacity retention rate of the supercapacitor is significantly greater than the sum of the increases when the modified gelatin and the crushing process of fibrous materials are used alone. This shows that the combined use of the pre-modified gelatin and the crushing process of fibrous materials can produce a synergistic effect and greatly improve the capacity retention rate of the supercapacitor.

[0038] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0039] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a supercapacitor dry electrode that prevents agglomeration and caking, comprising the following steps: S1. Raw material premixing stage: The activated carbon material and the conductive agent are dried and then placed in a ball mill for ball milling to obtain a mixed powder. The mixed powder and PTFE are added together in a high-speed mixer and stirred at high speed to obtain a premixed material, wherein the activated carbon material is prepared by mixing gelatin, tannic acid and carboxylated carbon nanotubes and then calcining at high temperature; S2 fiberization stage: The premixed material obtained in step S1 is added to the feeder of the jet mill, the operating pressure and temperature of the device are controlled, the material is fiberized to obtain a fiberized material; S3 re-crushing and rolling stage: The fiberized material of step S2 is compacted and then added to the crushing equipment for crushing to obtain a crushed powder, which is then subjected to high-temperature rolling to obtain a self-supporting carbon film; S4. Composite preparation of capacitor electrodes: The self-supporting carbon film obtained in step S3 is composited with carbon-coated aluminum foil under high temperature and high pressure to obtain a supercapacitor dry electrode that is anti-agglomeration.

2. The preparation method according to claim 1, characterized in that The preparation of the activated carbon material in step S1 includes the following: A1. Add 5 parts gelatin and 2-3 parts tannic acid, by weight, to 90-110 parts boric acid solution (the concentration of the boric acid solution is 0.8-1.2%), heat to 60-80°C, and stir for 20-40 minutes to obtain a pretreated gelatin solution. A2. Add 20-30 parts by mass of a 0.4-0.6% carboxylated carbon nanotube dispersion to the gelatin solution pretreated in step A1, stir for 2-4 hours, then heat to boiling, evaporate the solvent, and dry to obtain modified gelatin; A3. The modified gelatin obtained in step A2 is heated to 800-1000° C. at a heating rate of 3-10° C. / min under inert gas protection, calcined at a constant temperature for 3-5 hours, and naturally cooled to room temperature to obtain an activated carbon material.

3. The preparation method according to claim 1, characterized in that In step S1, the conductive agent is one or a mixture of two or more of acetylene black, SuperP and Ketjen black ECP.

4. The preparation method according to claim 1, characterized in that In step S1, the mass of the conductive agent accounts for 8-12% of the total mass of the mixed powder, and the mass of PTFE accounts for 6-10% of the total mass of the premixed material.

5. The preparation method according to claim 1, characterized in that In the drying process in step S1, the drying temperature is 100-180°C, the drying time is 12-24 hours, and the material is dried until the moisture content is below 1%.

6. The preparation method according to claim 1, characterized in that During the high-speed stirring process in step S1, the stirring temperature is 10-20° C., the stirring speed is 30-40 m / s, and the stirring time is 20-40 min.

7. The preparation method according to claim 1, characterized in that In step S2, the air flow mill has a working pressure of 0.5-0.9 MPa and a working temperature of 60-100°C.

8. The preparation method according to claim 1, characterized in that The compaction pressure in step S3 is 2-10 MPa, the rolling pressure in high-temperature rolling is 0.3-0.8 t / cm, the rolling temperature is 140-190° C., and the differential speed ratio of the two rollers is 1:

2.

9. The preparation method according to claim 1, characterized in that In step S3, the crushing process is to first cut the fibrous material into flocculent material with a diameter of 1-5 mm, and then crush the flocculent material into powdery material.

10. The preparation method according to claim 1, characterized in that Before lamination in step S4, the self-supporting carbon film and the carbon-coated aluminum foil are preheated at a temperature of 110-150°C. The lamination method is roller pressing at a pressure of 0.2-0.5 t / cm and a temperature of 140-180°C.

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